Investigation of Increase in Roughness Due to Environmental Factors in Flexible Pavements Using Profile Data From Long-Term Pavement Performance Specific Pavement Studies 1 Experiment

508 Descriptions

Figure 1. Equation. Formula for predicting the increase in IRI for new AC pavements and AC overlays of existing flexible pavements. IRI equals IRI subscript 0 plus 0.0150 multiplied by SF plus 0.4 multiplied by FC subscript Total plus 0.0080 multiplied by TC plus 40 multiplied by RD.

Figure 2. Equation. Formula for computing the SF. SF equals Age multiplied by the amount obtained by performing the following computation: PI plus 1 multiplied by 0.02003 plus Precip plus 1 multiplied by 0.007947 plus FI plus 1 multiplied by 0.000636.

Figure 3. Graph. Relationship between measured and predicted IRI from the MEPDG model for flexible pavements, from Mechanistic-Empirical Pavement Design Guide: A Manual of Practice, 2015, by the American Association of State Highway and Transportation Officials, Washington, D.C. Used by permission. This figure is a plot of the measured and the predicted International Roughness Index (IRI) for the data that was used to develop the IRI model for flexible pavements in the Mechanistic-Empirical Pavement Design Guide. This figure shows a graph with the y-axis labeled as predicted IRI with units of inches/mi, which ranges from 0 to 200 in increments of 50. The x-axis is labeled as measured IRI with units of inches/mi, which ranges from 0 to 200 in increments of 50. There is a wide scatter in the data around the line of equality, with the dispersion of the data points from the line of equality increasing with the magnitude of the measured IRI. A text box within the graph indicates N is equal to 1,926, R squared is 56 percent, and standard error of estimate is equal to 18.9 inches/mi.

Figure 4. Graph. Increase in IRI due to PI of subgrade predicted by the MEPDG model for four different PI values. This figure is a plot of how the predicted change in International Roughness Index (IRI) (inches/mi) that is predicted by the Mechanistic-Empirical Pavement Design Guide model changes with pavement age (years) for four different plasticity index (PI) values. The y-axis is labeled as predicted IRI change (inches/mi), which ranges from 0 to 0.3 in increments of 0.05. The x-axis is labeled as pavement age (years), which ranges from 0 to 20 in increments of 5. The figure shows how the predicted IRI change varies for pavement age from 1 to 20 years for the following four PI values: 10, 20, 30, and 40. The predicted IRI change increases linearly with pavement age for all four PI values. For PI = 10, the predicted IRI change increases from 0 to 0.07 inches/mi for pavement age from 1 to 20 years. For PI = 20, the predicted IRI change increases from 0.01 to 0.13 inches/mi for pavement age from 1 to 20 years. For PI = 30, the predicted IRI change increases from 0.01 to 0.19 inches/mi for pavement age from 1 to 20 years. For PI = 40, the predicted IRI change increases from 0.01 to 0.25 inches/mi for pavement age from 1 to 20 years.

Figure 5. Graph. Increase in IRI due to precipitation predicted by the MEPDG model for four different annual precipitation levels. This figure is a plot of how the predicted change in International Roughness Index (IRI) (inches/mi) that is predicted by the Mechanistic-Empirical Pavement Design Guide model changes with pavement age (years) for four different annual precipitation values. The y-axis is labeled as predicted IRI change (inches/mi), which ranges from 0 to 0.18 in increments of 0.02. The x-axis is labeled as pavement age (years), which ranges from 0 to 20 in increments of 5. This figure shows how the predicted IRI change changes from pavement age of 1 to 20 years for the following four precipitation values: 10 inches, 30 inches, 50 inches, and 70 inches. The predicted IRI change increases linearly with pavement age for all four precipitation values. For precipitation = 10 inches, the predicted IRI change increases from 0 to 0.03 in/mi for pavement age from 1 to 20 years. For precipitation = 30 inches, the predicted IRI change increases from 0 to 0.07 inches/mi for pavement age from 1 to 20 years. For precipitation = 50 inches, the predicted IRI change increases from 0.01 to 0.12 inches/mi for pavement age from 1 to 20 years. For precipitation = 70 inches, the predicted IRI change increases from 0.01 to 0.17 inches/mi for pavement age from 1 to 20 years.

Figure 6. Graph. Increase in IRI due to FI predicted by the MEPDG model for four different average annual FI values. This figure is a plot of how the predicted change in International Roughness Index (IRI) (inches/mi) that is predicted by the Mechanistic-Empirical Pavement Design Guide model changes with pavement age (years) for four different FI values. The y-axis is labeled as predicted IRI change (inches/mi), which ranges from 0 to 0.25 in increments of 0.05. The x-axis is labeled as pavement age (years), which ranges from 0 to 20 in increments of 5. This figure shows how the predicted IRI change changes from pavement age of 1 to 20 years for the following four FI values: 300 °F days, 600 °F days, 900 °F days, and 1,200 °F days. The predicted IRI change increases linearly with pavement age for all four FI values. For FI = 300 °F days, the predicted IRI change increases from 0 to 0.06 inches/mi for pavement age from 1 to 20 years. For FI = 600 °F days, the predicted IRI change increases from 0.01 to 0.11 inches/mi for pavement age from 1 to 20 years. For FI = 900 °F days, the predicted IRI change increases from 0.01 to 0.17 inches/mi for pavement age from 1 to 20 years. For FI = 1,200 °F days, the predicted IRI change increases from 0.01 to 0.23 inches/mi for pavement age from 1 to 20 years.

Figure 7. Equation. Formula for predicting the increase in IRI for new AC pavements and AC overlays of existing flexible pavements.⁽³⁾ IRI equals IRI subscript 0 plus 0.0150 multiplied by SF plus 0.4 multiplied by FC subscript Total plus 0.008 multiplied by TC plus 40 multiplied by RD.

Figure 8. Equation. Formula for computing SF.⁽³⁾ SF equals Age raised to the power of 1.5 multiplied by the sum of terms 1 and 2. Term 1 equals natural logarithm of Precip plus 1 multiplied by FI plus 1 multiplied by p subscript 02. Term 2 equals natural logarithm of Precip plus 1 multiplied by PI plus 1 multiplied by p subscript 200.

Figure 9. Graph. Change in IRI by fixing precipitation and FI and varying P₀₂. This figure is a plot of how the predicted International Roughness Index (IRI) change (inches/mi) changes with pavement age (years) for three different P₀₂ values with precipitation and freezing index fixed at 30 inches and 500 °F days, respectively. The y-axis is labeled as predicted IRI change (inches/mi), which ranges from 0 to 20 in increments of 2. The x-axis is labeled as pavement age (years), which ranges from 0 to 20 in increments of 5. This figure shows how the predicted IRI change changes for pavement age from 1 to 20 years for the following three P₀₂ values: 20 percent, 40 percent, and 60 percent. The predicted IRI change increases exponentially with pavement age for all three P₀₂ values. For P₀₂ = 20 percent, the predicted IRI change increases from 0.18 to 16.97 inches/mi for pavement age from 1 to 20 years. For P₀₂ = 40 percent, the predicted IRI change increases from 0.20 to 17.99 inches/mi for pavement age from 1 to 20 years. For P₀₂ = 60 percent, the predicted IRI change increases from 0.21 to 18.44 inches/mi for pavement age from 1 to 20 years.

Figure 10. Graph. Change in IRI by fixing FI and P₀₂ and varying average annual precipitation. This figure is a plot of how the predicted International Roughness Index (IRI) change (inches/mi) changes with pavement age (years) for three different average annual precipitation values with P₀₂ and freezing index fixed at 50 percent and 500 °F days, respectively. The y-axis is labeled as predicted IRI change (inches/mi), which ranges from 0 to 25 in increments of 5. The x-axis is labeled as pavement age (years), which ranges from 0 to 20 years in increments of 5. This figure shows how the predicted IRI change changes from pavement age of 1 to 20 years for the following three annual average precipitation values: 20 inches, 40 inches, and 60 inches. The predicted IRI change increases exponentially with pavement age for all three precipitation values. For precipitation = 20 inches, the predicted IRI change increases from 0.19 to 17.67inches/mi for pavement age from 1 to 20years. For precipitation = 40 inches, the predicted IRI change increases from 0.21 to 18.57inches/mi for pavement age from 1 to 20 years. For precipitation = 60 inches, the predicted IRI change increases from 0.21 to 19.10 inches/mi for pavement age from 1 to 20 years.

Figure 11. Graph. Change in IRI by fixing average annual precipitation and P₀₂ and varying average annual FI. This figure is a plot of how the predicted International Roughness Index (IRI) change (inches/mi) changes with pavement age (years) for three different freezing index (FI) values with P₀₂ and precipitation fixed at 50 percent and 30 inches, respectively. The y-axis is labeled as predicted IRI change (inches/mi), which ranges from 0 to 20 in increments of 2. The x-axis is labeled as pavement age (years), which ranges from 0 to 20 years in increments of 5. This figure shows how the predicted IRI change changes from pavement age of 1 to 20 years for the following three FI values: 100 °F days, 500 °F days, and 900 °F days. The predicted IRI change increases exponentially with pavement age for all three FI values. For FI = 100 °F days, the predicted IRI change increases from 0.18 to 16.05 inches/mi for pavement age from 1 to 20 years. For FI = 500 °F days, the predicted IRI change increases from 0.20 to 18.20 inches/mi for pavement age from 1 to 20 years. For FI = 900 °F days, the predicted IRI change increases from 0.21 to 18.98 inches/mi for pavement age from 1 to 20 years.

Figure 12. Graph. IRI progression at section 010106. This figure is a plot of how the left, right, and center IRI changed at section 010106 when pavement age increased from 4.3to 12.2 years. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 60 in increments of 10. The x-axis is labeled as pavement age (years), which ranges from 0 to 14 years in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 4.3, 4.9, 8, 9, 9.9, 11.2, and 12.2years. The left IRI values for the indicated pavement ages are 44, 48, 50, 52, 54, 54, and 54 inches/mi. The right values IRI for the indicated pavement ages are 37, 40, 42, 45, 45, 46, and 47 inches/mi. The center values IRI for the indicated pavement ages are 41, 39, 40, 44, 41, 41, and 43 inches/mi.

Figure 13 Graph. Time-sequence IRI values at section 010104. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 010104 when the pavement age increased from 4.3 to 12.2 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 70 in increments of 10. The x-axis is labeled as pavement age (years), which ranges from 0 to 14 years in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 4.3, 4.9, 5.1, 5.8, 8, 9, 9.9, 11.2, and 12.2 years. The left IRI values for the indicated pavement ages are 47, 45, 47, 50, 46, 48, 48, 47, and 49 inches/mi. The right IRI values for the indicated pavement ages are 38, 40, 42, 62, 39, 45, 40, 40, and 41 inches/mi. The center IRI values for the indicated pavement ages are 41, 38, 38, 38, 41, 46, 41, 42, and 42 inches/mi.

Figure 14. Graph. Profile data collected at section 010104 on 12/7/1998. This figure is a plot of the left, right, and center profile data collected at section 010104 on 12/7/1998 from 100 to 200 ft, with the profile data for each path offset for clarity. The y-axis is labeled as elevation (inches), which ranges from −1 to 1.5 in increments of 0.5. The x-axis is labeled as distance (ft), which ranges from 100 to 200 in increments of 20. The plot shows the profile data for the right has noise when compared with the data for the left and the center.

Figure 15. Graph. Profile data collected at section 260115 on 12/30/1996. This figure is a plot of the left, right, and center profile data collected at section 260115 on 12/30/1996 from 100 to 200 ft, with the profile data for each path offset for clarity. The y-axis is labeled as elevation (inches), which ranges from –0.5 to 2 in increments of 0.5. The x-axis is labeled as distance (ft), which ranges from 100 to 200 in increments of 20. The profile data for the left shows a sinusoidal pattern, and such a pattern is not seen for the right and the center data.

Figure 16. Graph. Time-sequence IRI values at section 010102. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 010102 when the pavement age increased from 4.3 to 12.2 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 250 in increments of 50. The x-axis is labeled as pavement age (years), which ranges from 0 to 14 in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 4.3, 4.9, 5.1, 5.4, 5.8, 8, 9, 9.9, 11.2, and 12.2 years. The left IRI values for the indicated pavement ages are 58, 59, 60, 67, 63, 85, 57, 140, 171, and 194 inches/mi. The right IRI values for the indicated pavement ages are 59, 70, 69, 91, 86, 94, 58, 144, 214, and 211 inches/mi. The center IRI values for the indicated pavement ages are 54, 55, 55, 58, 57, 58, 56, 58, 90, and 86 inches/mi.

Figure 17. Graph. Left wheelpath profile data at section 010102. This figure is a plot of the left wheelpath data collected at section 010102 on 3/14/2001, 3/10/2002, and 1/29/2003 from 0 to 500 ft, with the profile data for the three dates offset for clarity. The y-axis is labeled as elevation (inches), which ranges from −1.5 to 2 in increments of 0.5. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 100. It can be seen that the profile plot for the 3/10/2002 data is completely different from the profile plots obtained on 3/14/2001 and 1/29/2003. The profile plots for 3/14/2001 and 1/29/2003 show a similar shape.

Figure 18. Graph. Right wheelpath profile data at section 050122. This figure is a plot of the right wheelpath data collected at section 050122 on 4/6/2005, 5/22/2007, and 9/21/2008 from 0 to 500 ft, with the data collected for the three dates offset for clarity. The y-axis is labeled as elevation (inches), which ranges from −1.0 to 2.5 in increments of 0.5. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 100. The profile plots show that the profile plot for the 9/21/2008 data is different from the other two plots, with the other two plots showing a similar shape.

Figure 19. Graph. Time-sequence IRI values at section 260117. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 260117 when the pavement age increased from 1.5 to 16.9 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 160 in increments of 20. The x-axis is labeled as pavement age (years), which ranges from 0 to 20 in increments of 5. The left, right, and center IRI values are shown in this plot for pavement ages of 1.5, 1.6, 3, 3.4, 4.5, 6.6, 7.4, 9.5, 10.6, 12.5, 14, 15.8, 16.5, and 16.9 years. The left IRI values for the indicated pavement ages are 52, 55, 107, 95, 114, 137, 58, 69, 66, 69, 72, 73, 73, and 27 inches/mi. The right IRI values for the indicated pavement ages are 50, 50, 59, 61, 61, 63, 50, 50, 50, 55, 59, 59, 60, and 27 inches/mi. The center IRI values for the indicated pavement ages are 54, 50, 54, 53, 56, 60, 54, 56, 57, 59, 60, 61, 58, and 31 inches/mi. The left IRI value increases rapidly from 52 to 137 inches/mi as the pavement age increases from 1.5 to 6.6 years and then shows a sharp drop from pavement age of 6.6 to 7.4 years. The left, right, and center IRI values all show a sharp drop in IRI between pavement age of 16.5 and 16.9 years.

Figure 20. Graph. Time-sequence IRI values at section 200105. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 200105 as the pavement age increased from 3.3 to 7.5 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 200 in increments of 20. The x-axis is labeled as pavement age (years), which ranges from 0 to 8 in increments of 1. The left, right, and center IRI values are shown in this plot for pavement ages of 3.3, 4.8, 5.4, 6.4, and 7.5 years. The left IRI values for the indicated pavement ages are 96, 129, 173, 146, and 180 inches/mi. The right IRI values for the indicated pavement ages are 95, 142, 149, 140, and 176 inches/mi. The center IRI values for the indicated pavement ages are 59, 63, 68, 90, and 95 inches/mi.

Figure 21. Graph. Continuous IRI plot for center of the lane for section 200105. This figure shows continuous International Roughness Index (IRI) plots for the center of the lane at section 200105 for 3/21/1999 and 3/17/2000. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 250 in increments of 50. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The two plots agree with each other up to about 225 ft, but they are different thereafter. The plot for 3/17/2000 shows a sharp peak between 283 and 344 ft, and the IRI value at the peak is 232 inches/mi.

Figure 22. Graph. Continuous IRI plot for center of the lane for section 200106. This figure shows continuous International Roughness Index (IRI) plots for the center of the lane at section 200106 for 3/21/1999 and 3/17/2000. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 500 in increments of 50. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The two plots agree with each other up to about 270 ft, but after that, the plot for 3/17/2000 shows values that are higher than those for 3/21/1999 except at the end. The plot for 3/17/2000 shows a peak between 270 and 322 that occurs at 296 ft, and the IRI at the peak is 424 in/mi.

Figure 23. Graph. Continuous IRI plot for center of the lane for section 050119. This figure shows continuous International Roughness Index (IRI) plots for the center of the lane at section 050119 for 7/1/1997 and 1/22/2001. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 500 in increments of 50. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The two plots agree with each other fairly well except for between 155 and 249 ft, and 340 and 439 ft. Between 155 and 249 ft, the plot for 1/22/2001 has a peak at 205 ft with an IRI of 421 inches/mi. Between 340 and 439 ft, the plot for 1/22/2001 has a peak at 365 ft with an IRI of 445 inches/mi.

Figure 24. Graph. Continuous IRI plot for center of the lane for section 010102. This figure shows continuous International Roughness Index (IRI) plots for the center of the lane at section 010102 for 1/29/2003 and 4/27/2004. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 300 in increments of 50. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The plots agree with each other fairly well except for between 268 and 377 ft, and 432 and 484 ft. Between 268 and 377 ft, the plot for 4/27/2004 shows higher values compared with the plot for 1/29/2003, with a peak IRI of 249 inches/mi. Between 432 and 484 ft, the plot for 1/29/2003 shows higher values compared with the plot for 4/27/2004 with a peak IRI of 124 inches/mi.

Figure 25. Graph. Continuous IRI plot for center of the lane for section 190110. This figure shows continuous International Roughness Index (IRI) plots for the center of lane at section 190110 for 5/29/2001 and 8/6/2001. The y-axis is labeled as IRI (inches/mi), which ranges from 0to 600 in increments of 100. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The plots agree well with each other except for between 140 and 160 ft, and 300 and 320 ft. Between 140 and 160 ft, the plot for 5/29/2001 shows higher IRI values compared with the plot for 8/6/2001, with a sharp peak occurring for the 5/29/2001 data at 148 ft with an IRI of 491 inches/mi. Between 300 and 320 ft, the plot for 5/29/2001 shows higher IRI values compared with the plot for 8/6/2001, with a sharp peak occurring for the 5/29/2001 data at 310 ft with an IRI of 502 inches/mi.

Figure 26. Graph. Time-sequence IRI values at section 010418. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 010418 when the pavement age increased from 3.3 to 12.7 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 120 in increments of 20. The x-axis is labeled as pavement age (years), which ranges from 0 to 14 in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 3.5, 4.7, 5.3, 6.3, 7.4, 8.3, 8.6, 9.6, 10.6, 11.6 and 12.7 years. The left IRI for the indicated pavement ages are 35, 36, 35, 38, 37, 38, 38, 54, 54, 56, and 57 inches/mi. The right IRI for the indicated pavement ages are 73, 69, 72, 74, 78, 101, 103, 66, 74, 69, and 71 inches/mi. The center IRI for the indicated pavement ages are 38, 46, 40, 38, 38, 38, 38, 52, 68, 59, and 62 inches/mi.

Figure 27. Graph. Time-sequence IRI values at section 300109. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 300109 when the pavement age increased from 0.1 to 11.8 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 120 in increments of 20. The x-axis is labeled as pavement age (years), which ranges from 0 to 14 in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 0.1, 0.6, 1.8, 2.9, 4.0, 4.9, 5.8, 5.9, 6.7, 9.8, 10.8, and 11.8 years. The left IRI for the indicated pavement ages are 62, 61, 64, 61, 62, 63, 64, 64, 65, 70, 71, and 75 inches/mi. The right IRI for the indicated pavement ages are 69, 66, 64, 64, 65, 79, 104, 96, 103, 103, 111, and 109 inches/mi. The center IRI for the indicated pavement ages are 60, 57, 57, 59, 57, 58, 59, 63, 66, 63, 66 and 69 inches/mi.

Figure 28. Graph. Time-sequence IRI values at section 300123. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 300123 when the pavement age increased from 0.1 to 11.8 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 80 in increments of 10. The x-axis is labeled as pavement age (years), which ranges from 0 to 14 in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 0.1, 0.6, 1.8, 2.9, 4.0, 4.9, 5.8, 5.9, 6.7, 9.8, 10.8, and 11.8 years. The left IRI for the indicated pavement ages are 48, 49, 50, 51, 54, 55, 55, 61, 61, 64, 64, and 65 inches/mi. The right IRI for the indicated pavement ages are 55, 51, 51, 52, 53, 62, 63, 67, 68, 69, 69, and 72 inches/mi. The center IRI for the indicated pavement ages are 48, 48, 48, 47, 50, 50, 51, 58, 60, 65, 68, and 72 inches/mi.

Figure 29. Graph. Time-sequence IRI values at section 220116. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 220116 when the pavement age increased from 0.4 to 14.6 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 80 in increments of 10. The x-axis is labeled as pavement age (years), which ranges from 0 to 16 in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 0.4, 7.3, 9.1, 10.2, 10.8, 12.6, 13.7, and 14.6 years. The left IRI for the indicated pavement ages are 45, 48, 53, 49, 50, 65, 52, and 54inches/mi. The right IRI for the indicated pavement ages are 39, 44, 46, 47, 48, 68, 50, and 50inches/mi. The center IRI for the indicated pavement ages are 34, 45, 43, 47, 46, 60, 45, and 48 inches/mi.

Figure 30. Graph. IRI values obtained at section 220116 for different runs on 2/3/2101. This figure is a plot of the left, right, and center International Roughness Index (IRI) obtained at section 220116 for different runs performed on 2/3/2001. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 90 in increments of 10. The x-axis is labeled as profiler run, which ranges from 0 to 10 in increments of 1. IRI for left, right, and center for nine runs are shown in this plot. The left IRI for runs 1 to 9 are 82, 54, 58, 72, 76, 73, 49, 51, and 75 inches/mi. The right IRI for runs 1 to 9 are 83, 57, 55, 71, 81, 83, 46, 54, and 84 inches/mi. The center IRI for runs 1 to 9 are 85, 52, 42, 68, 74, 65, 45, 43, and 70 inches/mi.

Figure 31. Graph. Time sequence IRI values obtained at section 320107. This figure is a plot of how the left, right, and center International Roughness Index (IRI) changed at section 320107 when the pavement age increased from 1.6 to 13.8 years. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 140 in increments of 20. The x-axis is labeled as pavement age (years), which ranges from 0 to 16 in increments of 2. The left, right, and center IRI values are shown in this plot for pavement ages of 1.6, 2.2, 3, 4.1, 4.8, 5.8, 6.8, 6.9, 8.1, 8.6, 8.9, 11, and 13.8 years. The left IRI for the indicated pavement ages are 48, 48, 47, 45, 44, 46, 48, 48, 55, 60, 63, 94, and 119 inches/mi. The right IRI for the indicated pavement ages are 59, 58, 60, 60, 59, 58, 60, 60, 62, 64, 67, 84, and 107 inches/mi. The center IRI for the indicated pavement ages are 52, 53, 52, 52, 51, 52, 53, 53, 52, 54, 55, 63, and 81 inches/mi.

Figure 32. Graph. Continuous IRI plot for left wheelpath of section 320107. This figure shows continuous International Roughness Index (IRI) plots for the left wheelpath at section 320107 for 6/25/2009, 8/27/2006, and 8/4/2004. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 500 in increments of 100. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. For the plot corresponding to 6/25/2009, sharp peaks in IRI occur at distances of 36, 110, 132, 194, 271, 320, 347, 376, and 445 ft. For the plot corresponding to 8/27/2006, peaks in IRI occur at all these distances except at 194 ft. The IRI at the peaks for the data corresponding to 8/27/2006 have values lower than the IRI at the peaks for the data corresponding to 6/25/2009 except at 320 ft, where the IRI at the peak has a similar value for both dates. The data for 8/4/2004 show sharp peaks only at 320, 347, and 445 ft, and the IRI at these peaks is lower than the IRI values for both 8/27/2006 and 6/25/2009.

Figure 33. Graph. Left wheelpath profile data collected on 6/25/09 at section 320107. This figure is a plot of the left wheelpath profile data collected on 6/25/2009 at section 320107. The y‑axis is labeled as elevation (inches), which ranges from −1.4 to 0.6 in increments of 0.2. The x‑axis is labeled as distance (ft), which ranges from 0 to 500in increments of 50. Sharp downward spikes are seen in the plot at 32, 106, 127, 190, 267, 318, 333, 340, 343, 355, 373, and 440 ft.

Figure 34. Graph. Cumulative frequency distribution of sections based on pavement age at last profile date used for analysis. This figure is a cumulative frequency distribution plot of the sections based on pavement age at last profile date used for analysis. The y-axis is labeled as cumulative frequency (percent), which ranges from 0 to 100 in increments of 10. The x-axis is labeled as pavement age at last profile date used for analysis (years), which ranges from 0 to 18 in increments of 2. The x and y coordinates shown in this plot are (1,0), (2,0), (3,0), (4,0), (5,12.4), (6, 12.4), (7, 18.4), (8, 28.4), (9, 33.8), (10, 35.3), (11. 55.2), (12, 61.1), (13, 73.6), (14, 82.1), (15, 88.1), (16, 88.1), (17, 95.0), and (18, 100.0).

Figure 35. Graph. Cumulative frequency distribution of sections based on time span over which center lane data were collected. This figure is a cumulative frequency distribution plot of the sections based on time span over which center lane data were collected. The y-axis is labeled as cumulative frequency (percent), which ranges from 0 to 100 in increments of 10. The x-axis is labeled as period over which center lane data were collected (years), which ranges from 0 to 16 in increments of 2. The x and y coordinates shown in this plot are (1, 0.5), (2, 2.5), (3, 4.5), (4, 21.4), (5, 24.9), (6, 32.8), (7, 34.8), (8, 40.8), (9, 40.8), (10, 61.7), (11, 67.7), (12, 73.6), (13, 82.1), (14, 88.1), (15, 94.0), and (16, 100.0).

Figure 36. Graph. Box plots showing change in MIRI at test sections in each SPS-1 project. This figure shows box plots, with each box-plot showing the distribution of the change in mean International Roughness Index (MIRI) that occurred at the test sections in each SPS-1 project. The y-axis is labeled as change in MIRI (inches/mi), which ranges from −20 to 120 in increments of 20. The x-axis is labeled project location, and these are Alabama, Arizona, Arkansas, Delaware, Florida, Iowa, Kansas, Louisiana, Michigan, Montana, Nebraska, Nevada, New Mexico, Ohio, Oklahoma, Texas, Virginia, and Wisconsin. The box plot shows the following information for each project location: lower limit of data, first quartile value, median, third quartile value, and upper limit of data. The following are those values (inches/mi) in that order for each State shown in this plot: Alabama: 3, 4, 5, 6, 7; Arizona: 3, 8, 25, 41, 55; Arkansas: 14, 19, 20, 25, 34; Delaware: 0, 0, 1, 17, 23; Florida: 8, 13, 16, 20, 20; Iowa: 4, 11, 22, 24, 37; Kansas: 9, 10, 11, 16, 20; Louisiana: 4, 5, 8, 9, 10; Michigan: 3, 7, 9, 22, 35; Montana: 6, 10, 16, 51, 61; Nebraska: −1, 1, 3, 5, 8; Nevada: −2, 1, 4, 17, 42; New Mexico: 16, 27, 36, 54, 86; Ohio: 12, 17, 19, 26, 34; Oklahoma: 4, 7, 9, 17, 29; Texas: −6, −3, 1, 5, 8; Virginia: 1, 5, 7, 17, 30; and Wisconsin: 9, 12, 19, 34, 53. Outliers, if present, are shown as circles above the maximum value in each box plot. The projects where outliers are present, with the value of the outlier or outliers within parenthesis (inches/mi) are Alabama (10, 31), Arizona (97), Arkansas (38), Florida (34, 39), Iowa (80), Kansas (66), Louisiana (34), Michigan (49), Nebraska (13), Nevada (59, 118), Ohio (47), Oklahoma (51) and Virginia (45).

Figure 37. Graph. Box plots showing change in CLIRI at test sections in each SPS-1 project. This figure shows box plots, with each box plot showing the distribution of the change in center lane International Roughness Index (CLIRI) that occurred at the test sections in each Specific Pavement Studies 1 project. The y-axis is labeled as change in International Roughness Index (IRI) (inches/mi), which ranges from −20 to 120 in increments of 20. The x‑axis is labeled project location, and these are Alabama, Arizona, Arkansas, Delaware, Florida, Iowa, Kansas, Louisiana, Michigan, Montana, Nebraska, Nevada, New Mexico, Ohio, Oklahoma, Texas, Virginia, and Wisconsin. The box plot shows the following information at each project location: lower limit of data, first quartile value, median, third quartile value, and upper limit of data. The following are those values (inches/mi) in that order for each State shown in this plot: Alabama: 0, 1, 2, 4, 6; Arizona: 0, 1, 6, 13, 21; Arkansas: 2, 8, 10, 14, 17; Delaware: −4, −2, 0, 2, 7; Florida: 6, 10, 17, 28, 32; Iowa: 1, 7, 9, 16, 20; Kansas: 2, 3, 3, 6, 10; Louisiana: 7, 11, 13, 21, 24; Michigan: 4, 4, 6, 8, 9; Montana: 7, 11, 14, 21, 31; Nebraska: −1, 0, 4, 12, 28; Nevada: −1, 2, 3, 11, 12; New Mexico: 14, 29, 35, 58, 88; Ohio: 4, 8, 14, 21, 30; Oklahoma: −7, 0, 3, 5, 12; Texas: −6, −2, 2, 4, 8; Virginia: 4, 6, 9, 12, 13; and Wisconsin: 0, 2, 16, 30, 68. Outliers, if present, are shown as circles above the maximum value in each box plot. The projects where outliers are present, with the value of the outlier or outliers within parenthesis (inches/mi) are Florida (59, 101), Michigan (22), Nevada (30, 39), Texas (16), and Virginia (25).

Figure 38. Graph. Average time span over which IRI data have been collected at sections in SPS-1 projects. This figure is a bar graph that shows the average time span over which International Roughness Index (IRI) data have been collected at sections located in each Specific Pavement Studies 1 project. The y-axis is labeled as time span (years), which ranges from 0 to 16 in increments of 2. The x-axis is labeled project location, and they are Alabama, Arizona, Arkansas, Delaware, Florida, Iowa, Kansas, Louisiana, Michigan, Montana, Nebraska, Nevada, New Mexico, Ohio, Oklahoma, Texas, Virginia, and Wisconsin. The time spans for the projects are, Alabama—7 years, Arizona—6.8 years, Arkansas—9.6 years, Delaware—9 years, Florida—15.1 years, Iowa—3.7 years, Kansas—4.2 years, Louisiana—14.2 years, Michigan—5 years, Montana—11.7 years, Nebraska—3.1 years, Nevada—10.4 years, New Mexico—9.2 years, Ohio—7.1 years, Oklahoma—12.7 years, Texas—3 years, Virginia—11.4 years, and Wisconsin—10.3 years.

Figure 39. Graph. Rate of change of MIRI at test sections in each SPS-1 projects. This figure shows box plots, with each box plot showing the distribution of the rate of change of mean International Roughness Index (MIRI) that occurred at the test sections in each Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of MIRI (inches/mi), which ranges from −4 to 12 in increments of 2. The x-axis is labeled project location, and they are Alabama, Arizona, Arkansas, Delaware, Florida, Iowa, Kansas, Louisiana, Michigan, Montana, Nebraska, Nevada, New Mexico, Ohio, Oklahoma, Texas, Virginia, and Wisconsin. The box plot shows the following information at each project location: lower limit of data, first quartile value, median, third quartile value, and upper limit of data. The following are those values (inches/mi) in that order for each State shown in this plot: Alabama: −0.16, 0.22, 0.47, 0.71, 1.17; Arizona: 0.47, 1.12, 3.41, 5.61, 7.17; Arkansas: 1.22, 1.81, 2.22, 3.33, 3.90; Delaware: 0.10, 0.10, 0.26, 0.85, 2.30; Florida: 1.08, 1.29, 1.55, 1.93, 1.93; Iowa: 0.83, 2.86, 5.36, 5.92, 9.49; Kansas: 1.82, 2.15, 2.48, 4.51, 4.77; Louisiana: 0.55, 0.66, 0.82, 0.98, 0.98; Michigan: 0.44, 1.32, 2.42, 6.00, 9.59; Montana: 0.65, 1.01, 1.81, 5.03, 6.24; Nebraska: −1.27, −0.42, 0.26, 1.58, 3.87; Nevada: −0.35, −0.25, −0.03, 2.01, 4.29; New Mexico: 2.24, 3.11, 4.19, 6.88, 11.04; Ohio: 1.90, 2.11, 3.31. 5.34, 7.12; Oklahoma: 0.31, 0.56, 0.80, 1.32, 1.80; Texas: −1.74, −1.10, −0.12, 1.60, 3.82; Virginia: −0.28, 0.16, 0.66, 1.22, 1.34; and Wisconsin: 0.48, 1.22, 1.85, 4.30, 5.14. Outliers, if present, are shown as circles above the maximum value of the box plot. The projects where outliers are present, with the value of the outlier within parenthesis (inches/mi), are Alabama (8.19), Florida (3.05), Nevada (10.99), Oklahoma (5.38), and Virginia (3.09).

Figure 40. Graph. Rate of change of CLIRI at test sections in each SPS-1 projects. This figure shows box plots, with each box plot showing the distribution of the rate of change of CLIRI that occurred at the test sections in each SPS-1 project. The y-axis is labeled as the rate of change of CLIRI (inches/mi), which ranges from −4 to 12 in increments of 2. The x-axis is labeled project location, and they are Alabama, Arizona, Arkansas, Delaware, Florida, Iowa, Kansas, Louisiana, Michigan, Montana, Nebraska, Nevada, New Mexico, Ohio, Oklahoma, Texas, Virginia, and Wisconsin. The box plot shows the following information at each project location: lower limit of data, first quartile value, median, third quartile value, and upper limit of data. The following are those values (inches/mi/yr) in that order for each State shown in this plot: Alabama: −0.17, −0.06, 0.19, 0.74, 1.02; Arizona: −1.28, −0.62, 0.66, 0.97, 1.62; Arkansas: 0.18, 0.60, 0.97, 1.31, 1.55; Delaware: 0.19, 0.28, 0.75, 1.02, 1.12; Florida: 0.93, 1.04, 1.65, 2.24, 2.27; Iowa: 0.46, 1.73, 1.58, 4.61, 5.72; Kansas: 0.55, 0.64, 0.82, 1.70, 2.62; Louisiana: 0.76, 1.00, 1.18, 1.66, 2.02; Michigan: 0.96, 0.96, 1.47, 1.99, 2.05; Montana: 0.35, 0.92, 1.35, 2.03, 2.75; Nebraska: −1.20, 0.45, 1.79, 4.65, 9.21; Nevada: −0.43, −0.08, 0.08, 1.24, 2.61; New Mexico: 2.05, 3.31, 4.58, 7.24, 11.10; Ohio: 1.19, 1.32, 1.69, 4.16, 4.70; Oklahoma: −0.32, −0.02, 0.19, 0.46, 0.80; Texas:−2.74, −1.28, 0.04, 2.14, 5.09; Virginia: 0.14, 0.17, 0.34, 1.03, 1.07; and Wisconsin: -0.17, 0.01, 1.69, 3.21, 6.75. Outliers, if present, are shown as circles above the maximum value of the box plot. The projects where outliers are present, with the value of the outlier or outliers within parenthesis (inches/mi/yr), are Florida (4.05, 6.49), Michigan (4.61), and Virginia (3.28, 6.28).

Figure 41. Graph. Change in IRI at test sections in the Florida SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Florida Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 110 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section, and the second bar showing the change in CLIRI at the section. The sections shown on the x‑axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The change in MIRI and CLIRI in inches/mi in that order for the sections are section 7: 20, 101; section 2: 13, 17; section 5: 39, 14; section 1: 16, 27; section 3: 34, 24; section 8: 8, 59; section 10: 15, 8; section 11: 19, 6; section 9: 12, 21; section 6: 20, 32; section 12: 14, 7; and section 4: 18, 11.

Figure 42. Graph. Rate of change of IRI at test sections in the Florida SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Florida Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 7 in increments of 1. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 7: 2.0, 6.5; section 2: 1.1, 1.3; section 5: 3.2, 1.4; section 1: 1.5, 2.1; section 3: 3.0, 1.9; section 8: 1.2, 4.1; section 10: 1.4, 1.0; section 11: 1.8, 0.9; section 9: 1.3, 1.9, section 6: 1.9, 2.3; section 12: 1.5, 0.9; and section 4: 1.6, 1.3.

Figure 43. Graph. Change in IRI at test sections in the Louisiana SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Louisiana Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 40 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 34, 24; section 20: 5, 13; section 22: 5, 10; section 21: 9, 22; section 19: 4, 7; section 14: 8, 22; section 17: 9, 21; section 18: 9, 12; section 15: 8, 13; section 16: 10, 14; section 23: 5, 14; and section 24: 5, 10.

Figure 44. Graph. Rate of change of IRI at test sections in the Louisiana SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Louisiana Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 3 in increments of 0.5. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 2.7, 2.0; section 20: 0.7, 1.2; section 22: 0.6, 1.0; section 21: 1.0, 1.9; section 19: 0.5, 0.8; section 14: 0.9, 1.7; section 17: 1.0, 1.5; section 18: 1.0, 1.2; section 15: 0.8, 0.9; section 16: 1.0, 1.1; section 23: 0.7, 1.1; and section 24: 0.7, 1.1.

Figure 45. Graph. Change in IRI at test sections in the Oklahoma SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Oklahoma Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index IRI (inches/mi), which ranges from 0 to 60 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 51, –1; section 20: 23, 2; section 22: 11, 5; section 21: 29, 5; section 19: 4. −2; section 14: 8, 0; section 17: 12, 4; section 18: 7, 3; section 15: 8, −7; section 16: 5, 2; section 23: 16, 12; and section 24: 9, 6. A note on the graph states: Monitoring period 9.4 years for Section 13 and 22, and 13.3 years for other sections.

Figure 46. Graph. Rate of change of IRI at test sections in the Oklahoma SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and rate of change of center lane International Roughness Index (CLIRI) at test sections in the Oklahoma Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −1 to 6 in increments of 1. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 5.4, 0; section 20: 1.4, 0.1; section 22: 1.1, 0.6; section 21: 1.8, 0.3; section 19: 0.3, −0.1; section 14: 0.6, 0; section 17: 0.9, 0.2; section 18: 0.5, 0.3; section 15: 0.6, −0.3; section 16: 0.5, 0.2; section 23: 1.1, 0.8; and section 24: 0.7, 0.5. A note on the graph states: Monitoring period 9.4 years for Section 13 and 22, and 13.3 years for other sections.

Figure 47. Graph. Change in IRI at test sections in the Montana SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Montana Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 80 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 61, 16; section 20: 73, 24; section 22: 47, 31; section 21: 61, 20; section 19: 26, 8; section 14: 16, 18; section 17: 14, 11; section 18: 10, 11; section 15: 8, 14, section 16: 6, 7; section 23: 17, 24; and section 24: 10, 14.

Figure 48. Graph. Rate of change of IRI at test sections in the Montana SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (IRI) and center lane International Roughness Index (CLIRI) at test sections in the Montana Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (in/mi), which ranges from 0 to 7 in increments of 1. The x‑axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 5.2, 1.3; section 20: 6.2, 2.1; section 22: 4.5, 2.7; section 21: 5.4, 1.9; section 19: 2.7, 0.9; section 14: 1.9, 0.3; section 17: 1.7, 1.1; section 18:1.0, 1.0; section 15: 0.8, 1.4, section 16:0.6, 0.7; section 23: 1.7, 2.2; and section 24: 1.1, 1.4.

Figure 49. Graph. Change in IRI at test sections in the Nevada SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Nevada Specific Pavement Studies 1 project. This y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 130 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 7: 59, 30; section 2: 118, 11; section 5: −2, −1; section 1: 9, 3; section 3: −2, 0; section 8: 5, 4; section 10: 8, 6; section 11: 4, 12; section 9: 42, 39; section 6: 1, 3; section 12: 0, 1; section 4: 1, 3. A note on the graph states: All test sections were not monitored for same period. See table 61.

Figure 50. Graph. Rate of change of IRI at test sections in the Nevada SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Nevada Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −2 to 12 in increments of 2. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 7: 4.3, 1.8; section 2: 11.0, 1.4; section 5: −0.3, −0.4; section 1: −0.3, 0; section 3: −0.3, −0.1; section 8: 0.1, 0.1; section 10: 0.3, 0.3; section 11: 0, 0.6; section 9: 2.6, 2.6; section 6: 0, 0; section 12: 0, −0.1; section 4: −0.1, 0.1. A note on the graph states: All test sections were not monitored for same period. See table 61.

Figure 51. Graph. Change in IRI at test sections in the Virginia SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Virginia Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index IRI (inches/mi), which ranges from 0 to 50 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 30, 11; section 20: 20, 12; section 22: 2, 6; section 21: 45, 9; section 19: 10, 10; section 14: 20, 15; section 17: 5, 4; section 18: 10, 13; section 15: 3, 5; section 16: 1, 6; section 23: 7, 4; and section 24: 6, 25. A note shown on the graph states: Sections were monitored over different time periods. See table 63.

Figure 52. Graph. Rate of change of IRI at test sections in the Virginia SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Virginia Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −1 to 8 in increments of 1. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The rate of change in MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 7.4, 3.3; section 20: 1.3, 0.9; section 22: 0.3, 0.1; section 21: 3.1, 0.3; section 19: 0.9, 0.6; section 14: −0.3, 0.2; section 17: 0.6, 0.4; section 18: 0.7, 1.1; section 15: 0.1, 0.2; section 16: −0.1, 0.2; section 23: 0.5, 0.2; and section 24: 0.9, 3.7. A note on the graph states: Sections were monitored over different time periods. See table 63.

Figure 53. Graph. Change in IRI at test sections in the Wisconsin SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Wisconsin Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 80 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the changes in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLRI (inches/mi) in that order for the sections are section 13: 12, 16; section 20: 10, 1; section 22: 12, 0; section 21: 9, 3; section 19: 19, 2; section 14: 11, 24; section 17: 48, 68; section 18: 34, 47; section 15: 53, 21; section 16: 35, 57; section 23: 19, 16; and section 24: 24, 15.

Figure 54. Graph. Rate of change of IRI at test sections in the Wisconsin SPS-1 project. This figure is a bar graph that show the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index(CLIRI) at test sections in the Wisconsin Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −1 to 8 in increments of 1. The x-axis is labeled as section number (weakest to strongest) and shows section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 1.4, 1.7; section 20: 0.9, −0.1; section 22: 1.4, −0.2; section 21: 0.5, 0; section 19: 2.0, 0.1; section 14: 1.2, 2.7; section 17: 4.7, 6.8; section 18: 4.4, 3.4; section 15: 5.1, 1.7; section 16: 4.0, 5.3; section 23: 1.7, 1.7; and section 24: 2.1, 1.4.

Figure 55. Graph. Change in IRI at test sections in the Alabama SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Alabama Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 40 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for 11 sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the change in mean IRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The change in MIRI and CLIRI (inches/ mi) in that order for the sections are section 2: 31, 4; section 5: 4, 6; section 1: 7, 5; section 3: 5, 0; section 8: 4, 1; section 10: 5, 3; section 11: 4, −1; section 9: 5, 1; section 6: 10, 2; section 12: 6, 4; and section 4: 3, 1. A note shown on the graph states: Monitoring period: Section 2—3.7 years, other sections—7.9 years.

Figure 56. Graph. Rate of change of IRI at test sections in the Alabama SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Alabama Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −1 to 9 in increments of 1. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for 11sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar graph showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 2: 8.2, 1.0; section 5: 0.5, 0.8; section 1: 0.6, 1.0; section 3: 0.4, −0.1; section 8: 0.2, −0.1; section 10: −0.2, 0; section 11: 0.4, −0.2; section 9: 0.8, 0.1; section 6: 1.2, 0.3; section 12: 0.5, 0.6; and section 4:0.3, 0.5. A note shown on the graph states: Monitoring period: Section 2—3.7 years, other sections—7.9 years.

Figure 57. Graph. Change in IRI at test sections in the Arizona SPS-1 project that had data over a 5.1-year period. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Arizona Specific Pavement Studies 1 project that have been monitored for 5.1years. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 40 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for seven sections. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 14, 18, 16. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 29, 10; section 20: 5, 6; section 22: 3, 0; section 21: 5, 1; section 14: 9, 6; section 18: 16, 0; and section 16: 28, 0.

Figure 58. Graph. Change in IRI at test sections in the Arizona SPS-1 project that had data over a 9.2-year period. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Arizona Specific Pavement Studies 1 project that have been monitored for 9.2years. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 110 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows section numbers for five sections in the project. Two bars shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 19, 17, 15, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 19: 33, 13; section 17: 41, 13; section 15: 97, 21; section 23: 42, 4; and section 24: 55, 13.

Figure 59. Graph. Rate of change of IRI for test sections in the Arizona SPS-1 project that had data over a 5.1-year period. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Arizona Specific Pavement Studies 1 project that have been monitored for 5.1 years. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −2 to 8 in increments of 1. The x-axis is labeled as section number (weakest to strongest) and shows section numbers for seven sections in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 14, 18, 16. The change in MIRI and CLIRI (inches/mi in that order for the sections are section 13: 7.0, 1.6; section 20: 1.0, 0.6; section 22: 0.7, −0.5; section 21: 0.5, −0.7; section 14: 1.9, 1.0; section 18: 3.3, −0.7; and section 16: 3.5, −1.3.

Figure 60. Graph. Rate of change of IRI at test sections in the Arizona SPS-1 project that had data over a 9.2-year period. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Arizona Specific Pavement Studies 1 project that have been monitored for 9.2 years. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi), which ranges from 0 to 8 in increments of 1. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for five sections in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 19, 17, 15, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 19: 2.7, 0.8; section 17: 4.0, 0.8; section 15: 7.2, 1.5; section 23: 3.9, 0; and section 24: 6.1, 0.7.

Figure 61. Graph. Change in IRI at test sections in the Arkansas SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Arkansas Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 40 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows section numbers for 10 sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 22, 21, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 38, 17; section 22: 26, 13; section 21: 25, 2; section 14: 34, 12; section 17: 19, 9; section 18: 19, 8; section 15: 16, 10; section 16: 14, 5; section 23: 20, 16; and section 24: 24, 14. A note shown on the graph states: Monitoring Period: Section 21—6.8 years, other sections—9.9 years.

Figure 62. Graph. Rate of change of IRI at test sections in the Arkansas SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Arkansas Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 5 in increments of 0.5. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for the 10 sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 22, 21, 14, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 3.9, 1.5; section 22: 2.4, 1.2; section 21: 3.4, 0.2; section 14: 3.3, 1.1; section 17: 1.9, 0.8; section 18: 1.8, 0.7; section 15: 1.7, 0.9; section 16: 1.2, 0.4; section 23: 2.0, 1.6; and section 24: 2.4, 1.3. A note shown on the graph states: Monitoring Period: Section 21—6.8 years, other sections—9.9 years.

Figure 63. Graph. Change in IRI at test sections in the Delaware SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Delaware Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 30 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 7: 21, −3; section 2: 23, 7; section 5: 17, 1; section 1: 20, −1; section 3: 6, 3; section 8: 1, 2; section 10: 1, 0; section 11: 0, –2; section 9: 0, −4; section 6: 0, 3; section 12: 1, 0; and section 4: 1, −2.

Figure 64. Graph. Rate of change of IRI at test sections in the Delaware SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Delaware Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 2.5 in increments of 0.5. The x‑axis is labeled as section number (weakest to strongest) and the shows section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 7: 2.3, 0.4; section 2: 2.1, 1.1; section 5: 1.9, 0.8; section 1: 1.8, 0.3; section 3: 0.9, 1.1; section 8: 0.3, 1.1; section 10: 0.3, 1.0; section 11: 0.1, 0.4; section 9: 0, 0.2; section 6: 0.1, 0.9; section 12: 0.2, 0.7; and section 4: 0.1, 0.2.

Figure 65. Graph. Change in IRI at test sections in the New Mexico SPS-1 project. This figure is a bar graph that show the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the New Mexico Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 100 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 7: 62, 66; section 2: 51, 55; section 5: 27, 32; section 1: 64, 66; section 3: 86, 88; section 8: 24, 28; section 10: 16, 14; section 11: 25, 23; section 9: 32, 37; section 6: 31, 29; section 12: 48, 56; and section 4: 34, 35.

Figure 66. Graph. Rate of change of IRI at test sections in the New Mexico SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the New Mexico Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 12 in increments of 2. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bar graphs are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 7: 7.6, 7.9; section 2: 6.5, 6.8; section 5: 4.1, 4.6; section 1: 7.0, 7.5; section 3: 11.0, 11.1; section 8: 2.8, 3.2; section 10: 2.2, 2.0; section 11: 2.9, 2.7; section 9: 4.0, 4.6; section 6: 3.8, 3.6; section 12: 5.8, 6.7; and section 4: 4.2, 4.1.

Figure 67. Graph. Center of lane profile data collected at section 12 in the New Mexico project for two different test dates. This figure is a plot of the center of the lane profile data collected from 100 to 200 ft at section 12 in the New Mexico project on 3/11/1997 and 1/9/2003, with the data plots offset for clarity. The y-axis is elevation (inches), which ranges from 0 to 0.35in increments of 0.05. The x-axis is labeled as distance (ft), which ranges from 100 to 200 in increments of 10. The profile data collected on 1/9/2003 shows a high scatter when compared with the data collected on 3/11/1997.

Figure 68. Graph. Change in IRI at test sections in the Ohio SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Ohio Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 50 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for eight sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 3, 8, 10, 11, 9, 6, 12, and 4. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 3: 22, 14; section 8: 16, 15; section 10: 12, 4; section 11: 19, 9; section 9: 17, 5; section 6: 23, 27; section 12: 34, 30; section 4: 47, 19. A note shown on the graph states: Monitored period different for sections, see table 77.

Figure 69. Graph. Rate of change of IRI at test sections in the Ohio SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Ohio Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 14 in increments of 2. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers of eight sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 3, 8, 10, 11, 9, 6, 12, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 3: 6.0, 4.5; section 8: 5.0, 4.6; section 10: 7.0, 4.9; section 11: 8.0, 5.0: section 9: 9.0, 5.2; section 6: 10.0, 6.3; section 12: 11.0, 6.4; and section 4: 12.0, 7.1. A note shown on the graph states: Monitored period different for sections, see table 77.

Figure 70. Graph. Change in IRI at test sections in the Iowa SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Iowa Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 90 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 7: 4, 1; section 2: 80, 21; section 5: 22, 11; section 1: 28, 11; section 3: 23, 20; section 8: 37, 9; section 10: 23, 20; section 11: 11, 7; section 9: 5, 5; section 6: 14, 9; section 12: 11, 8; and section 4: 23, 14.

Figure 71. Graph. Rate of change of IRI at test sections in the Iowa SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Iowa Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 25 in increments of 5. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 7, 2, 5, 1, 3, 8, 10, 11, 9, 6, 12, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 7: 0.8, 0.5; section 2: 20.8, 5.7; section 5: 5.1, 2.8; section 1: 7.0, 2.9; section 3:5.9, 5.0; section 8: 9.5, 2.1; section 10: 5.7, 5.1; section 11:2.9, 1.7; section 9: 1.2, 1.2; section 6: 3.5, 2.4; section 12: 3.0, 1.9; and section 4: 5.6, 3.4.

Figure 72. Graph. Change in IRI at test sections in the Kansas SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Kansas Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 70 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for seven sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 3, 8, 10, 11, 9, 12, and 4. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 3: 66, 10; section 8: 13, 3; section 10: 9, 5; section 11: 11, 7; section 9: 20, 3; section 12: 10, 2; and section 4: 11, 3.

Figure 73. Graph. Rate of change of IRI at test sections in the Kansas SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Kansas Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 16 in increments of 2. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for the seven sections in the project for which data were available. Two bars shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 3, 8, 10, 11, 9, 1 2, and 4. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 3: 14.6, 2.6; section 8: 4.8, 0.8; section 10: 1.8, 1.3; section 11: 2.3, 1.7; section 9: 4.4, 0.5; section 12: 2.3, 0.6; and section 4: 2.5, 0.8.

Figure 74. Graph. Change in IRI at test sections in the Michigan SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Michigan Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 60 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for the eight sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 20, 21, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 20: 3, 8; section 21: 18, 4; section 17: 49, 6; section 18: 35, 22; section 15: 16, 9; section 16: 9, 4; section 23: 3, 7; and section 24: 8, 4. A note shown on the graph states: Monitoring Period: Section 21—3.6 years, Other sections—5.2 years.

Figure 75. Graph. Rate of change of IRI at test sections in the Michigan SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Michigan Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 12 in increments of 2. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers for eight sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 20, 21, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches /mi/yr) in that order for the sections are section 20: 1.2, 1.8; section 21: 5.6, 1.0; section 17: 9.6, 1.5; section 18: 6.2, 4.6; section 15: 3.0, 2.1, section 16: 1.8, 0.9; section 23: 0.4, 0.9; and section 24: 1.6, 1.4. A note on the graph states: Monitoring Period: Section 21—3.6 years, Other sections—5.2 years.

Figure 76. Graph. Change in IRI at test sections in the Nebraska SPS-1 project. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Nebraska Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from −5 to 30 in increments of 5. The x-axis is labeled as section number (weakest to strongest) and the shows section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 5, 28; section 20: 2, 3; section 22: 0, −1; section 21: 13, 14; section 19: 1, −3; section 14: 8, 12; section 17: 2, 8; section 18: −1, 4; section 15: 5, 13; section 16: 3, 8; section 23: −2, 0; and section 24: 4, 0.

Figure 77. Graph. Rate of change of IRI at test sections in the Nebraska SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Nebraska Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −2 to 10 in increments of 2. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of center lane CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 0.2, 9.2; section 20: −0.1, 1.5; section 22: −0.5, 0.2; section 21: 3.9, 5.1; section 19: 0, −1.2; section 14:2.9, 1.6; section 17: 0.3, 3.2; section 18: −0.5, 2.0; section 15: 1.8, 4.9; section 16: 0.8, 3.9; section 23: −1.3, 0.4; and section 24: 0.7, 0.7.

Figure 78. Graph. Change in IRI at test sections in the Texas SPS-1 project. This figure is a bar graph that show the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Texas Specific Pavement Studies 1 project. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from −10 to 20 in increments of 5. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: −3, −2; section 20: 8, 8; section 22: −3, −1; section 21: 5, 3; section 19: 5, −2; section 14: 7, 8; section 17: 4, −6 ; section 18: 1, −2; section 15: −5, −3; section 16: −4, 3; section 23: −1, 2; and section 24: −6, 16. A note shown on the graph states: Time period over which data were available were different for test sections, see table 87.

Figure 79. Graph. Rate of change of IRI at test sections in the Texas SPS-1 project. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Texas Specific Pavement Studies 1 project. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −4 to 6 in increments of 1. The x-axis in the figure as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: −0.9, -0.3; section 20: 1.9, 2.2; section 22: −1.2, −0.2; section 21: 0.5, 0.3; section 19: 2.9, −1.5; section 14: 3.8, 2.2; section 17: 0.7, −1.8; section 18: 0.3, −0.7; section 15: −1.7, −2.7; section 16: −0.9, 1.9; section 23: −0.5, 0.3; and section 24: −1.7, 5.1. A note on the graph states: Time periods over which data were available were different for test sections, see table 87.

Figure 80. Graph. Change in IRI at the Michigan SPS-1 project after overlay. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Michigan Specific Pavement Studies 1 project after the overlay. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 30 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers of the eight sections in the project for which data were available. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 20, 21, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 20: 10, 9; section 21: 4, 6; section 17: 13, 4; section 18: 8, 5; section 15: 27, 22; section 16: 11, 7; section 23: 1, 6; and section 24: 3, 9.

Figure 81. Graph. Rate of change of IRI for sections in the Michigan SPS-1 project after overlay. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Michigan Specific Pavement Studies 1 project after the overlay. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from 0 to 4 in increments of 0.5. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers of the eight sections for which data were available. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 20, 21, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 20: 1.5, 1.5; section 21: 0.5, 0.8; section 17: 1.3, 0.6; section 18: 1.1, 0.7; section 15: 3.6, 2.9; section 16: 1.3, 0.9; section 23: 0.5, 0.7; and section 24: 0.5, 1.2.

Figure 82. Graph. Change in IRI at the Texas SPS-1 project after overlay. This figure is a bar graph that shows the change in mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Texas Specific Pavement Studies 1 project after the overlay. The y-axis is labeled as International Roughness Index (IRI) (inches/mi), which ranges from 0 to 30 in increments of 10. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the change in MIRI at the section and the second bar showing the change in CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The change in MIRI and CLIRI (inches/mi) in that order for the sections are section 13: 9, −4; section 20: 21, 8; section 22: 16, 4; section 21: 6, 5; section 19: 19, 4; section 14: 4, 6; section 17: 6, –5; section 18: 12, −1; section 15: 7, 7, section 16: 4, 5; section 23: 24, 7; and section 24: 15, 5.

Figure 83. Graph. Rate of change of IRI for sections in the Texas SPS-1 project after overlay. This figure is a bar graph that shows the rate of change of mean International Roughness Index (MIRI) and center lane International Roughness Index (CLIRI) at test sections in the Texas Specific Pavement Studies 1 project after the overlay. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr), which ranges from −2 to 10 in increments of 2. The x-axis is labeled as section number (weakest to strongest) and shows the section numbers in the project. Two bars are shown for each section, with the first bar showing the rate of change of MIRI at the section and the second bar showing the rate of change of CLIRI at the section. The sections shown on the x-axis are in the following order: 13, 20, 22, 21, 19, 14, 17, 18, 15, 16, 23, and 24. The rate of change of MIRI and CLIRI (inches/mi/yr) in that order for the sections are section 13: 1.8, −0.8; section 20: 7.3, 2.0; section 22: 7.0, 1.0; section 21: 1.9, 1.3; section 19: 5.4, 1.2; section 14: 1.0, 1.6; section 17: 2.4, −1.5; section 18: 4.5, 0.1; section 15: 2.2, 1.9; section 16: 1.7, 1.5; section 23: 8.0, 1.6; and section 24: 7.5, 2.6.

Figure 84. Graph. Change in center of lane IRI versus change in mean IRI. This figure is a plot that shows the relationship between the change in center lane International Roughness Index (CLIRI) and change in mean International Roughness Index (MIRI) at the test sections. The y‑axis is labeled AS change in CLIRI (inches/mi), which ranges from 0 to 120 in increments of 10. The x-axis is labeled as change in MIRI (inches/mi) and also ranges from 0 to 120 in increments of 10. The line of equality is shown on the graph. Most of the data points are within the region bounded by change in MIRI less than 40 inches/mi and change in CLIRI less than 30 inches/mi. There are more points below the line of equality than above the line of equality. The plot shows a general trend of CLIRI increasing with increasing values of MIRI.

Figure 85. Graph. Rate of change of center of lane IRI versus rate of change of MIRI. This figure is a plot that shows the relationship between the rate of change of center line International Roughness Index (CLIRI) and rate of change of mean International Roughness Index (MIRI) at the test sections. The y-axis is labeled as rate of change of CLIRI (inches/mi/yr), which ranges from −2 to 22 in increments of 2. The x-axis is labeled as rate of change in MIRI (inches/mi) and also ranges from −2 to 22 in increments of 2. The line of equality is shown on the graph. Most of the data points are within the region bounded by rate of change of MIRI less than 6 inches/mi/yr and rate of change of CLIRI less than 6 inches/mi/yr. There are more points below the line of equality than there are points above the line of equality. The plot shows a general trend of rate of change of CLIRI increasing with increasing values of rate of change of MIRI.

Figure 86. Graph. Box plots showing rate of change of MIRI and CLIRI. This figure presents two box plots that show the rate of change of IRI, one for the mean rate and the other for the center lane rate. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plot for mean rate is shown first followed by the box plot for the center rate. The lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data, in this order for the mean rate and center rate shown on each box plot in units of inches/mi/yr are mean rate: −1.74, 0.53, 1.49, 3.17, 7.12; and center rate: −1.79, 0.31, 1.04, 1.91, 4.09. Outliers are shown as solid circles above each box plot. For the mean rate, three outliers are shown, with the value of the outliers ranging from 7.17 to 9.48 inches/mi/yr. For the center rate, nine outliers are shown, with the value of the outliers ranging from 4.57 to 9.21 inches/mi/yr.

Figure 87. Graph. Relationship between rate of change of MIRI and SN of test sections. This figure is a plot that shows the relationship between the rate of change of mean International Roughness Index (MIRI) and structural number of the test sections. The y-axis is labeled as rate of change of MIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The x-axis is labeled as SN and ranges from 0 to 9 in increments of 1. The values for the rate of change of MIRI are shown for the SNs of the test sections, which range from 2.8 to 7.7. A trend line is shown on the plot that shows a decreasing rate of change of MIRI with increasing values of SN. The equation of the fitted trend line is shown on the plot, which is y is equal to −0.2762 multiplied by x plus 3.4408. The R squared value of the trend line is also shown on the plot and is equal to 0.03.

Figure 88. Graph. Relationship between rate of change of CLIRI and SN of test sections. This figure is a plot that shows the relationship between the rate of change of center lane International Roughness Index (CLIRI) and structural number (SN) of the test sections. The y‑axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The x-axis is labeled as SN and ranges from 0 to 9 in increments of 1. The graph shows the values of the rate of change of CLIRI for the SNs of the test sections, which range from 2.8 to 7.7. A trend line is shown on this plot, which is almost horizontal. The equation of the trend line is shown on the plot, which is y is equal to −0.0617 multiplied by x plus 1.7948. The R squared value of the trend line is also shown on the plot and is equal to 0.002.

Figure 89. Graph. Box plots showing rate of change of MIRI and CLIRI for weak and strong sections. This figure presents box plots that show the rate of change of mean International Roughness Index (MIRI) for weak and strong sections, and the rate of change of center line International Roughness Index (CLIRI) for weak and strong sections. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plots are shown in the following order: MIRI—Weak, CLIRI—Weak, MIRI–Strong, and CLIRI—Strong. For the four box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as MIRI—Weak: −0.89, 1.01, 2.02, 6.02, 8.19; CLIRI—Weak: −0.32, 0.50, 1.49, 3.03, 3.28; MIRI—Strong: −1.74, 0.66, 1.46, 2.06, 6.21; and CLIRI–Strong: −1.79, 0.28, 0.97, 1.90, 4.09. Outliers greater than the upper limit of data are shown as solid circles above each box plot. No outliers are present for MIRI–Weak. Five outliers are shown for CLIRI—Weak, with the value of the outliers ranging from 5.72 to 9.21inches/mi/yr. Two outliers are shown for MIRI—Strong, whose values are 6.99 and 9.49inches/mi/yr. Five outliers are shown for CLIRI—Strong, with the values of the outliers ranging from 4.57 to 7.46 inches/mi/yr.

Figure 90. Graph. Box plots showing the rate of change of MIRI and CLIRI for sections on fine-grained and coarse-grained subgrade. This figure presents box plots that show the rate of change of mean International Roughness Index (MIRI) for sections on fine-grained and coarse-grained subgrade, and the rate of change of center lane International Roughness Index (CLIRI) for sections on fine-grained and coarse-grained subgrade. The y-axis is labeled as rate of change of International Roughness Index (IRI) (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box-plots are shown in the following order: MIRI Fine-Grained, MIRI Coarse-Grained, CLIRI Fine-Grained, and CLIRI Coarse-Grained. For the four box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as MIRI Fine-Grained: −1.27, 0.65, 1.87, 4.45, 9.49; MIRI Coarse-Grained: −1.74, 0.48, 1.43, 2.69, 5.40; CLIRI Fine-Grained: −1.20, 0.95, 1.65, 3.49, 6.79; and CLIRI Coarse-Grained: −1.47, 0.18, 0.78, 1.45, 3.43. Outliers greater than the upper limit of the data are shown as solid circles above each box plot. There is one outlier for MIRI Fine-Grained, whose value is 9.59 inches/mi/yr. There are three outliers for MIRI Coarse-Grained, whose values range from 6.13 to 7.36 inches/mi/yr. There are three outliers for CLIRI Fine-Grained, whose values range from 7.46 to 9.21 inches/mi/yr. There are seven outliers for CLIRI Coarse-Grained, whose values range from 3.43 to 6.75 inches/mi/yr. For all box plots, there is only one outlier shown that is below the lower limit of the data, which is for CLIRI Coarse-Grained and has a value of −1.79 inches/mi/yr.

Figure 91. Graph. Box plots showing the rate of change of MIRI for sections with and without drainage, categorized according to subgrade type. This figure presents box plots that show the rate of change of mean International Roughness Index (MIRI) for sections on coarse-grained subgrade with and without drainage and the rate of change of MIRI for sections on fine-grained subgrade with and without drainage. The y-axis is labeled as rate of change of MIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box-plots are shown in the following order: Coarse—No Drainage, Coarse—Drainage, Fine—No Drainage, and Fine—Drainage. For the four box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data in this order are shown in units of inches/mi/yr as Coarse—No Drainage: −1.74, 0.50, 1.55, 3.31, 7.36; Coarse—Drainage: −1.70, 0.50, 1.40, 2.34, 4.77; Fine—No Drainage: −0.51, 0.89, 2.72, 5.92, 9.59; and Fine—Drainage: −1.27, 0.53, 1.24, 3.43, 7.64. Outliers are shown as solid circles above each box plot. There are no outliers for Coarse—No Drainage and Fine—No Drainage. There are two outliers for Coarse—Drainage, with values of 5.40 and 6.17 inches/mi/yr. There is one outlier for Fine—Drainage, with a value of 9.49 inches/mi/yr.

Figure 92. Graph. Box plots showing the rate of change of CLIRI for sections with and without drainage, categorized according to subgrade type. This figure presents box plots that show the rate of change of center lane International Roughness Index (CLIRI) for sections on coarse-grained subgrade with and without drainage and the rate of change of CLIRI for sections on fine-grained subgrade with and without drainage. The y-axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box-plots are shown in the following order: Coarse—No Drainage, Coarse—Drainage, Fine—No Drainage, and Fine—Drainage. For the four box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as Coarse—No Drainage: −1.28, 0.18, 0.85, 1.46, 3.28; Coarse—Drainage: −1.47, 0.19, 0.66, 1.36, 2.75; Fine—No Drainage: −0.07, 1.23, 2.40, 9.21; and Fine—Drainage: −1.20, 0.61, 1.23, 1.97, 3.20. Outliers are shown as solid circles above each box plot. There are no outliers for Fine—No Drainage. There are three outliers for Coarse—No Drainage, with the values ranging from 3.43 to 6.75 inches/mi/yr. There are four outliers for Coarse—Drainage, with the values ranging from 3.68 to 6.49 inches/mi/yr. There are four outliers also for Fine—Drainage, with the values ranging from 4.57 to 7.88 inches/mi/yr. There is only outlier lower than the lower limit of the data, which is shown as a solid circle below the lower limit of data, and this occurs for Coarse—No Drainage, with a value of −1.79 inches/mi/yr.

Figure 93. Graph. Box plots showing the rate of change of MIRI for sections on fine-grained subgrade, categorized according to type of drainage. This figure presents box plots that show the rate of change of mean International Roughness Index (MIRI) for sections without drainage, sections where drainage consists of permeable asphalt-treated base (PATB)/dense graded aggregate base (DGAB), and sections where drainage consists of asphalt-treated base (ATB)/PATB. The y-axis is labeled as rate of change of MIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plots are shown in the following order: No Drainage, PATB/DGAB, and ATB/PATB. For the three box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as No Drainage: −0.51, 0.89, 2.72, 5.92, 9.59; PATB/DGAB: −0.14, 0.60, 1.24, 3.55, 9.49, and ATB/PATB: −1.27, 0.50, 1.12, 2.88, 5.75. No outliers are shown for any box plot.

Figure 94. Graph. Box plots showing the rate of change of CLIRI for sections on fine-grained subgrade, categorized according to type of drainage. This figure presents box plots that show the rate of change of center lane International Roughness Index (CLIRI) for sections without drainage, sections where drainage consists of permeable asphalt-treated base (PATB)/ dense graded aggregate base (DGAB), and sections where drainage consists of asphalt-treated base (ATB)/PATB. The y-axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plots are shown in the following order: No Drainage, PATB/DGAB, and ATB/PATB. For the three box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in in units of inches/mi/yr as No Drainage: −0.07, 1.23, 2.40, 4.58, 9.21; PATB/DGAB: −1.20, 0.61, 1.32, 2.67, 5.07, and ATB/PATB: −0.17, 0.63, 1.16, 1.81, 2.72. Outliers greater than the upper limit of the data are shown for PATB/DGAB and ATB/PATB as solid circles above the upper limit of the data. There is one outlier for PATB/DGAB with a value of 7.88 inches/mi/yr, and two outliers for ATB/PATB with values of 5.11 and 6.70 inches/mi/yr.

Figure 95. Graph. Box plots showing the rate of change of MIRI at SPS-1 sections according to environmental zone. This figure presents box plots that show the rate of change of mean International Roughness Index (MIRI) for sections located in the environmental zones of dry-freeze (DF), dry-no freeze (DNF), wet-freeze (WF), and wet-no freeze (WNF). The y-axis is labeled as rate of change of MIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plots are shown in the following order: DF, DNF, WF, and WNF. For the three box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as DF: −0.35, −0.02, 1.03, 3.13, 6.24; DNF: 0.47, 2.79, 3.97, 6.23, 7.64; WF: −1.21,1.24, 2.48, 4.91, 9.59; and WNF: −1.74, 0.43, 0.86, 1.80, 3.94. Outliers greater than the upper limit of the data are shown as solid circles above the upper limit of the data, and outliers are only present for WNF. There are three outliers for WNF with values ranging from 5.38 to 8.19 inches/mi/yr.

Figure 96. Graph. Box plots showing the rate of change of CLIRI at SPS-1 sections according to environmental zone. This figure presents box plots that show the rate of change of center lane International Roughness Index (CLIRI) for sections located in the environmental zones of dry-freeze (DF), dry-no freeze (DNF), wet-freeze (WF), and wet-no freeze (WNF). The y-axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plots are shown in the following order: DF, DNF, WF, and WNF. For the four box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as DF: −0.43, 0.08, 0.96, 1.53, 2.75; DNF: −1.28, 0.70, 1.83, 4.58, 7.88; WF: −01.20, 0.99, 1.70, 3.01, 5.72, and WNF: −0.69, 0.20, 0.80, 1.23, 2.27. Outliers are shown as solid circles below the lower limit of the data or above the upper limit of the data on each box plot. Outliers lower than the lower limit are seen only for WNF, with values of −1.79 and −1.49 inches/mi/yr. Outliers above the upper limit of the data are seen for WF and WNF. For WF there are two outliers, with values of 6.75 and 9.21 inches/mi/yr. For WNF, there are five outliers with values ranging from 3.28 to 6.49 inches/mi/yr.

Figure 97. Graph. Box plots showing the rate of change of MIRI at sections in DNF, WNF, and WF zones, categorized according to subgrade type. This figure presents box plots that show the rate of change of mean International Roughness Index (MIRI) for sections based on environmental zone and subgrade type. The box plots shown are in the following order: Dry-No Freeze (DNF)—Coarse, DNF—Fine, Wet-Freeze (WF)—Coarse, WF—Fine, Wet-No Freeze (WNF)—Coarse, and WNF—Fine. The y-axis is labeled as rate of change of MIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. For the six box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as DNF—Coarse: 0.47, 1.69, 3.41, 4.57, 7.17; DNF—Fine: 2.24, 3.56, 4.29, 6.66, 7.64; WF—Coarse: 0.48, 1.59, 2.26, 4.42, 5.14; WF—Fine: −1.27, 0.81, 2.80, 5.47, 9.59; WNF—Coarse: −1.74, 0.29, 1.09, 1.90, 3.94, and WNF—Fine: -0.16, 0.48, 0.67, 0.96, 1.17. Outliers greater than the upper limit of the data are shown for each box plot above the upper limit as solid circles. Outliers are present only for WNF—Coarse and WNF—Fine. There are two outliers for WNF—Coarse as well as for WNF—Fine. The values for WNF—Coarse are 5.38 and 7.96 inches/mi/yr, while the values for WNF—Fine are 2.71 and 8.19 inches/mi/yr.

Figure 98. Graph. Box plots showing the rate of change of CLIRI for sections in DNF, WNF, and WF zones, categorized according to subgrade type. This figure presents box plots that show the rate of change of center lane International Roughness Index (CLIRI) for sections based on environmental zone and subgrade type. The box plots shown are in the following order: Dry-No Freeze (DNF)—Coarse, DNF—Fine, Wet-Freeze (WF)—Coarse, WF—Fine, Wet-No Freeze (WNF)—Coarse, and WNF—Fine. The y-axis of the box plot is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. For the six box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as DNF—Coarse: −1.28, −0.52, 0.66, 0.84, 1.62; DNF—Fine: 2.05, 3.53, 4.58, 6.95, 7.88; WF—Coarse: −0.17, 0.59, 1.36, 2.18, 5.39; WF—Fine: −1.20, 1.29, 1.86, 3.56, 5.72; WNF—Coarse: −0.69, 0.20, 0.67, 1.26, 2.27; and WNF—Fine: −0.17, 0.25, 0.92, 1.15, 2.02. Outliers lower than the lower limit of the data are shown as solid circles below the lower limit of the data in a box plot. Such outliers are only seen for WNF—Coarse, with the values of −1.79 and −1.47 inches/mi/yr. Outliers greater than the upper limit of the data are shown for each box plot above the upper limit of the data as solid circles, and such outliers are seen for WF—Coarse, WF—Fine and WNF—Coarse. There is one outlier for WF—Coarse and WF—Fine with values of 6.75 and 9.21 inches/mi/yr, respectively. There are five outliers for WNF—Coarse with values ranging from 3.28 to 6.49 inches/mi/yr.

Figure 99. Graph. Rate of change of CLIRI versus percent subgrade passing through the No. 200 sieve for SPS-1 sections in the wet no-freeze zone. This figure is a plot of the rate of change of center lane International Roughness Index (CLIRI) (inches/mi/yr) versus the percent subgrade passing through the No. 200 sieve for the Specific Pavement Studies 1 (SPS-1) project sections in the wet no-freeze zone. The y-axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The x-axis is labeled as percent subgrade passing the No. 200 sieve and ranges from 0 to 100 in increments of 10. The values on the x-axis corresponding to the data shown on the plot are 9.6, 30.4, 62.7, 71.2, 87.9, and 98.9 percent. The rates of change of CLIRI are shown for the sections in each SPS-1 project corresponding to each value shown on the x-axis. The minimum and maximum values of rate of change of CLIRI in units of inches/mi/yr for each value of percent subgrade passing through the No. 200 are 9.6 percent: −0.17, 6.75: 30.4 percent: 0.55, 2.62; 62.7 percent: 0.93, 4.61; 71.2 percent: 1.19. 4.67; 87.9: 0.41, 5.72; and 98.9 percent: −1.26, 4.90. A weak trend of increasing rate of change of CLIRI with increasing percent subgrade passing through the No. 200 sieve is seen in this plot. The trend line fitted to the data is shown on the graph. The equation of the trend line is y equals 0.0122 multiplied by x plus 1.5529. The R squared value of the trend line is 0.0375.

Figure 100. Graph. Rate of change of CLIRI versus percent material passing through the No. 200 sieve for SPS-1 sections in the WNF zone. This figure is a plot of the rate of change of center lane International Roughness Index (CLIRI (inches/mi/yr) versus the percent subgrade passing through the No. 200 sieve for the Specific Pavement Studies 1 (SPS-1) sections in the wet no-freeze zone. The y-axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 7 in increments of 1. The x-axis is labeled as percent subgrade passing through the No. 200 sieve and ranges from 0 to 100 in increments of 10. The values on the x-axis corresponding to the data shown on the plot are 11.7, 18.1, 25.5, 36.9, 43.1, 66.5, and 94.4 percent. The rates of change of CLIRI are shown for the sections in each SPS-1 project corresponding to each value shown on the x-axis. The minimum and maximum values of rate of change of CLIRI in units of inches/mi/yr for each value of percent subgrade passing through the No. 200 are11.7 percent: −1.79, 5.09: 18.1 percent: 0.18, 4.05; 25.5 percent: 0.19, 1.11; 36.9 percent: −0.32, 0.80; 43.1 percent: 0.14, 3.68; 66.5 percent: −0.17, 1.02; and 94.4 percent: 0.76, 2.02. No relationship between rate of change of CLIRI and percent subgrade passing through the No. 200 sieve is seen in the plot. The trend line fitted to the data is shown on the graph. The equation of the trend line is y equals minus 0.0004 multiplied by x plus 0.8793. The R squared value of the trend line is 1E-04.

Figure 101. Graph. Box plots showing rate of change of MIRI for sections on fine-grained subgrade, categorized according to environmental zone and provision of drainage. This figure presents box plots showing the rate of change of mean International Roughness Index (MIRI) for sections on fine-grained subgrade categorized according to environmental zone and provision of drainage. Box plots are for the following cases: Dry-No Freeze (DNF)—No Drainage, DNF—Drainage, Wet-Freeze (WF)—No Drainage, WF—Drainage, Wet-No Freeze (WNF)—No Drainage, and WNF—Drainage. The y-axis is labeled as rate of change of MIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plots are shown in the following order: DNF—No Drainage, DNF—Drainage, WF—No Drainage, WF—Drainage, WNF—No Drainage, and WNF—Drainage. For the six box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as DNF—No Drainage: 3.79, 4.17, 5.39, 6.88, 6.99; DNF—Drainage: 2.24, 2.84, 3.47, 5.34, 7.64; WF—No Drainage: −0.51, 1.83, 3.01, 6.07, 9.59; WNF—Drainage: −1.27, 0.65, 1.90, 3.91, 9.49; WNF—No Drainage: 0.28, 0.56, 0.93, 1.03, 1.17; and WNF—Drainage: −0.16, 0.36, 0.59, 0.67, 0.96. Outliers greater than the upper limit of the data are shown above the upper limit of the data as solid circles on a box plot, and such outliers are only seen for WNF—No Drainage, which has two outliers, with values of 2.71 and 8.91 inches/mi/yr.

Figure 102. Graph. Box plots showing rate of change of CLIRI for sections on fine-grained subgrade, categorized according to environmental zone and provision of drainage. This figure presents box plots showing the rate of change of center line International Roughness Index (CLIRI) for sections on fine-grained subgrade, categorized according to environmental zone and provision of drainage. Box plots are for the following cases: Dry-No Freeze (DNF)—No Drainage, DNF—Drainage, Wet-Freeze (WF)—No Drainage, WF–Drainage, Wet-No Freeze (WNF)—No Drainage, and WNF–Drainage. The y-axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The box plots are shown in the following order: DNF—No Drainage, DNF—Drainage, WF—No Drainage, WF—Drainage, WNF—No Drainage, and WNF—Drainage. For the six box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as, DNF–No Drainage: 3.64, 4.21, 5.68, 7.29, 7.46; DNF—Drainage: 2.05, 2.84, 3.89, 6.17, 7.88; WF—No Drainage: 0.93, 2.00, 2.88, 4.66, 5.72; WNF—Drainage: 0.17, 0.93, 1.33, 1.82, 2.13; WNF—No Drainage: -0.07, 0.72, 0.99, 1.30, 2.02; and WNF–Drainage: −0.17, 0.01, 0.66, 1.12, 1.86. Only WF—Drainage has an outlier with a value lower than the lower limit of data; it is shown as a solid circle below the lower limit of the box plot and has a value of −1.20 inches/mi/yr. Outliers greater than the upper limit of the data are seen for WF—No Drainage and WF—Drainage; these appear as solid circles above the upper limit of the data in these box plots. WF—No Drainage has one outlier with a value of 9.21 inches/mi/yr, while WF—Drainage has two outliers with values of 4.67 and 5.07 inches/mi/yr.

Figure 103. Graph. Rate of change of MIRI of test sections located on fine-grained subgrade vs. the PI of the subgrade. This figure is a plot of the rate of change of the mean International Roughness Index (MIRI) (inches/mi/yr) against plasticity index (PI) of the subgrade (percent) for the test sections located on fine-grained subgrade. The y-axis is labeled as rate of change of MIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The x-axis is labeled as PI of subgrade (percent) and ranges from 0 to 30 in increments of 5. The values on the x-axis corresponding to the data shown on the plot are: 10.3, 15, 16.7, 20, 20.3, 27.7, and 30 percent. The rates of change of MIRI are shown for the sections in each Specific Pavement Studies 1 project corresponding to each value shown on the x-axis. The minimum and maximum values of rate of change of MIRI in units of inches/mi/yr are shown for each value of PI: 10.3 percent: 0.44, 9.59; 15 percent: 1.90, 7.12; 16.7 percent: −0.16, 8.19; 20 percent: 0.55, 0.98; 20.3 percent: 0.27, 3.87; 27.7 percent: 0.83, 9.49; and 30 percent: 2.24, 7.64. The trend line fitted to the data is shown on the graph, and it shows a trend of increasing rate of change of MIRI with increasing values of PI. The equation of the trend line is y equals 0.1744 multiplied by x minus 0.6524. The R squared value of the trend line is shown on the graph as 0.1014.

Figure 104. Graph. Rate of change of CLIRI of test sections located on fine-grained subgrade versus the PI of the subgrade. This figure is a plot between the rate of change of center lane International Roughness Index (CLIRI) (inches/mi/yr) and plasticity index (PI) of the subgrade (percent) for the test sections located on fine-grained subgrade. The y-axis is labeled as rate of change of CLIRI (inches/mi/yr) and ranges from −2 to 10 in increments of 2. The x-axis is labeled as PI of subgrade (percent) and ranges from 0 to 35 in increments of 5. The values on the x axis corresponding to the data shown on the plot are: 10.3, 15, 16.7, 20, 20.3, 27.7, and 30 percent. The rates of change of CLIRI are shown for the sections in each Specific Pavement Studies 1 project corresponding to each value shown on the x-axis. The minimum and maximum values of rate of change of CLIRI in units of inches/mi/yr for each value of PI are: 10.3 percent: 0.93, 4.61; 15 percent: 1.19, 4.70; 16.7 percent: −0.12, 1.20; 20 percent: 0.70, 1.88; 20.3 percent: −1.20, 4.90; 27.2 percent: 0.46, 5.72; and 30 percent: 2.05, 11.10. The trend line fitted to the data is shown on the graph, and it shows a trend of increasing rate of change of MIRI with increasing values of PI. The equation of the trend line is y equals 0.181 multiplied by x plus 1.3417. The R squared value of the trend line is shown as equal to 0.239.

Figure 105. Graph. Relationship between the change in CLIRI and length of transverse cracking at test sections. This figure is a plot that shows the relationship between the change in center lane International Roughness Index (CLIRI) and total length of transverse cracking at the test sections. The y-axis is labeled as change in International Roughness Index (IRI) (inches/mi) and ranges from −10 to 80 in increments of 10. The x-axis is labeled as total length of transverse cracking (ft) and ranges from 0 to 400 in increments of 50. The data shown on the plot does not show any relationship between the change in CLIRI and total length of transverse cracking. Many sections shown on this plot have 0 transverse cracking and a change in CLIRI ranging from −6 to 68 inches/mi. The trend line fitted to the data is shown on the graph. The equation of the trend line is y equals 0.0255 multiplied by x plus 10.896. The R squared value of the trend line is shown as equal to 0.0144.

Figure 106. Graph. CLIRI values at section 300114 in Montana. This figure is a plot of 22 center of lane International Roughness Index (CLIRI) values obtained at section 300114 in the Montana Specific Pavement Studies 1 project from 7/21/2000 to 8/16/2004. The y-axis is labeled as CLIRI (inches/mi) and ranges from 40 to 60 in increments of 2. The x-axis is labeled as profile date and shows 22 dates. The CLIRI on 7/21/2000 is 46 inches/mi, while the CLIRI on 8/16/2004 is 55 inches/mi. The other IRI values shown on this plot are for the following dates: 9/13/2000, 11/14/2000, 2/27/2001, 4/10/2001, 6/13/2001, 8/10/2001, 10/15/2001, 1/18/2002, 2/6/2002, 4/3/2002, 9/26/2002, 12/12/2002, 1/20/2003, 3/12/2003, 8/27/2003, 10/17/2003, 12/8/2003, 1/22/2004, 4/19/2004, and 7/21/2004. CLIRI for these dates range from 45 to 49 inches/mi.

Figure 107. Graph. CLIRI values at section 320101 in Nevada. This figure is a plot of 15 center of lane International Roughness Index (CLIRI) values obtained at section 320101 in the Nevada Specific Pavement Studies 1 project from 3/8/1997 to 12/16/2001. The y-axis is labeled as International Roughness Index (IRI) (inches/mi) and ranges from 48 to 55 in increments of 1. The x-axis is labeled as profile date and shows 15 dates. The IRI on 3/8/1997 is 52 inches/mi, while the IRI on 12/16/2001 is also 52 inches/mi. The other IRI values shown on this plot are for the following dates: 3/8/1997, 4/22/1997, 8/2/1997, 9/16/1997, 11/18/1997, 2/3/2000, 4/20/2000, 6/14/2000, 9/11/2000, 11/17/2000, 2/26/2001, 4/18/2001, 6/19/2001, 10/23/2001, and 12/16/2001. IRI for these dates range from 50 to 54 inches/mi.

Figure 108. Graph. CLIRI values at section 510114 in Virginia. This figure is a plot of 18 center of lane International Roughness Index (CLIRI) values obtained at section 510114 in the Virginia Specific Pavement Studies 1 project from 1/16/1998 to 11/8/2003. The y-axis is labeled as CLIRI (inches/mi) and ranges from 62 to 67 in increments of 1. The x-axis is labeled as profile date and shows 18 dates. The CLIRI on 1/16/1998 is 63 inches/mi, while the CLIRI on 11/8/2003 is 64 inches/mi. The other CLIRI values shown on this plot are for the following dates: 3/8/1997, 4/22/1997, 8/2/1997, 9/16/1997, 11/18/1997, 2/3/2000, 4/20/2000, 6/14/2000, 9/11/2000, 11/17/2000, 2/26/2001, 4/18/2001, 6/19/2001, 10/23/2001, and 12/16/2001. The CLIRI for these dates range from 63 to 66 in/mi.

Figure 109. Graph. Continuous IRI plot showing the change in IRI along the center of lane at section 350105. This figure shows the continuous International Roughness Index (IRI) plots for the center of lane at section 350105 for 3/11/1997 and 4/24/2006. The y-axis of the graph is labeled as IRI (inches/mi), which ranges from 0 to 140 in increments of 20. The x-axis of the plot is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The continuous IRI plot for 4/24/2006 shows higher values than the continuous IRI plot for 3/11/1997 except between 13 to 16 ft and 41 to 56 ft.

Figure 110. Graph. PSD plot for center of lane data at section 350105. This figure shows the power spectral density (PSD) plot of the center of the lane data at section 350105 for 3/11/1997 and 4/24/2006. The y-axis is labeled as slope spectral density (ft/cycle), which ranges from 1.0E-07 to 1.0E-03 in increments of 1.0E-01. The x-axis is labeled as wavelength (ft), which ranges from 0.1 to 1,000. Both the x- and y-axes are plotted in the logarithmic scale. The PSD plot for 4/24/2006 has higher spectral content than that for the data for 3/11/1997 for wavelengths less than 83 ft. Thereafter, up to a wavelength of 670 ft, which is the limit of the data, the data for 3/11/1997 have higher spectral content than data for 4/24/1996.

Figure 111. Graph. Continuous IRI plot showing the change in IRI along the center of lane at section 220114. This figure shows the continuous International Roughness Index (IRI) plots for the center of lane at section 220114 for 11/17/1997 and 1/16/2012. The y-axis is labeled as IRI (inches/mi), which ranges from 0 to 100 in increments of 10. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The continuous IRI plot for 1/16/2012 shows higher values than the continuous IRI plot for 11/17/1997 throughout the section.

Figure 112. Graph. PSD plot for center of lane data at section 220114. This figure is the power spectral density (PSD) plot of the center of the lane data at section 220114 for 11/17/1997 and 1/16/2012. The y-axis is labeled as slope spectral density (ft/cycle), which ranges from 1.0E-08 to 1.0E-03 in increments of 1.0E-01. The x-axis of the plot is labeled as wavelength (ft), which ranges from 0 to 1,000. Both the x- and y-axes are plotted in the logarithmic scale. The PSD plot corresponding to 1/16/2012 has higher spectral content than that for the data corresponding 11/17/1997 for most wavelengths except a few wavelengths greater than 30 ft.

Figure 113. Graph. Center of lane profile plot at section 300122. This figure is the center of the lane profile plot for the data collected at section 300122 on 11/16/2012. The y-axis is labeled as elevation (inches), which ranges from −0.8 to 0.6 in increments of 0.2. The x-axis of the plot is labeled as distance (ft), which ranges from 0 to 500 in increments of 100. Sharp downward features are shown on this plot at distances 129, 247, and 465 ft.

Figure 114. Graph. Continuous IRI plot showing the change in IRI along the center of lane at section 300122. This figure shows the continuous International Roughness Index (IRI) plots for the center of lane at section 300122 for 11/17/1997 and 1/16/2012. The y-axis is labeled as center lane IRI (inches/mi), which ranges from 0 to 250 in increments of 50. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The continuous IRI plot for 1/16/2012 shows four distinct peaks of high magnitude that are not seen for the data corresponding to 11/17/1997. The peak IRI values occurred at distances of 137, 248, 375, and 465 ft with the IRI values at these peaks being 195, 195, 134, and 165 inches/mi, respectively.

Figure 115. Graph. Center of lane profile at section 390112. This figure is the center of the lane profile plot for the data collected at section 390112 on 5/23/2012 The y-axis is labeled as elevation (inches), which ranges from −0.8 to 0.6 in increments of 0.2. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 100. Downward spikes are seen in the profile plot at many locations.

Figure 116. Graph. Continuous IRI plot showing the change in IRI along the center of lane at section 390112. This figure shows the continuous International Roughness Index (IRI) plots for the center of the lane at section 390112 for 11/12/1998 and 5/23/2012. The y-axis is labeled as center of lane IRI (inches/mi), which ranges from 0 to 350 in increments of 50. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The continuous IRI plot for 5/23/2012 shows higher values than that for the 11/12/1998 plot throughout the section except in a few isolated areas.

Figure 117. Graph. Center of lane profile plot at section 040119. This figure is the center of the lane profile plot for the data collected at section 040119 on 3/27/2006. The y-axis is labeled as elevation (inches), which ranges from −0.4 to 0.6 in increments of 0.2. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. Some sharp downward spikes are seen in the profile plot at several locations.

Figure 118. Graph. Continuous CLIRI plot at section 040119. This figure shows the continuous International Roughness Index (IRI) plots for the center of the lane at section 040119 for 1/23/1997 and 3/27/2006. The y-axis is labeled as center lane IRI (inches/mi), which ranges from 0 to 140 in increments of 20. The x-axis is labeled as distance (ft), which ranges from 0 to 500 in increments of 50. The continuous IRI plot for 3/27/2006 shows higher IRI values than the plot for 1/23/1997 for the majority of the section. The continuous IRI plot for 3/27/2006 shows the largest increase in IRI with the plot for 1/23/1997 between 70 and 200 ft.

Figure 119. Graph. Box plots showing the change in CLIRI, classified according to the subgrade type. This figure presents box plots showing the change in center lane International Roughness Index (CLIRI) for sections on coarse-grained and fine-grained subgrade. The y-axis is labeled as change in CLIRI (inches/mi) and ranges from −20 to 120 in increments of 20. The box plot for the coarse-grained subgrade is shown first in the figure followed by the box plot for the fine-grained subgrade. For the two box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of inches/mi/yr as coarse-grained: −7.0, 2.0, 6.5, 14.1, 31; and fine-grained: −3.0, 4.4, 9.9, 20.6, 37. Outliers greater than the upper limit of the data are shown as solid circles above the upper limit of the data in each box plot. Coarse-grained has six outliers that range from 32 to 101 inches/mi, while fine-grained has three outliers that range from 55 to 85 inches/mi.

Figure 120. Graph. Box plots showing the period over which CLIRI was collected at the test sections, classified according to the subgrade type. This figure presents box-plots of the time period over which center lane International Roughness Index (CLIRI) was collected at the test sections located on coarse-grained and fine-grained subgrade. The y-axis is labeled as time period for change in CLIRI (years) and ranges from 0 to 16 in increments of 2. In this figure, the box-plot for coarse-grained subgrade is shown first followed by the box-plot for the fine-grained subgrade. For the two box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of years as coarse-grained: 2.0, 7.0, 11.0, 12.8, 15.0; and fine-grained: 1.0, 3.7, 6.0, 9.1, 14.

Figure 121. Graph. Box plots showing the age of the pavement at the last profile date used for analysis classified according to subgrade type. This figure presents box plots for the age of pavement at last profile date for test sections located on coarse-grained and fine-grained subgrade. The y-axis is labeled as pavement age (years) and ranges from 0 to 20 in increments of 2. In this figure, the first box-plot shown is for the coarse-grained subgrade and the second box-plot shown is for the fine-grained subgrade. For the two box plots, the lower limit of data, first quartile of data, median of data, third quartile of data, and upper limit of data (in that order) are shown in units of years as coarse-grained: 4.2, 9.8, 11.8, 13.7, 17.4; and fine-grained: 4.6, 6.6, 9.3, 12.2, 16.6.

Figure 122. Equation. Formula for model developed for predicting the change in the center of lane IRI considering all data. ΔCLIRI equals 0.42 multiplied by Elapsed Time multiplied by the natural logarithm of sum of Term 1 and Term 2. Term 1 equals to natural logarithm of Precip plus 1 multiplied by P200 multiplied by FI plus 1. Term 2 equals to PI plus 1 multiplied by natural logarithm of Precip plus 1. For this equation, R squared equals to 0.43, standard error equals to 14.9 inches/mi, and data points is equal to 201.

Figure 123. Equation. Formula for model developed for predicting the change in the center lane of lane IRI considering sections on coarse-grained subgrade. ΔCLIRI equals 0.4522 multiplied by Elapsed Time multiplied by natural logarithm of Term 1. Term 1 equals to natural logarithm of Precip plus 1 multiplied by P200 multiplied by FI plus 1. For this formula, R squared equals 0.37, standard error equals 14.2 inches/mi, and data points equal 125.

Figure 124. Equation. Formula for model developed for predicting the change in the center lane of lane IRI considering sections on fine-grained subgrade. ΔCLIRI equals to 0.4304 multiplied by Elapsed Time multiplied by the natural logarithm of sum of Term 1 and Term 2. Term 1 equals natural logarithm of Precip plus 1 multiplied by P200 multiplied by FI plus 1. Term 2 equals PI plus 1 multiplied by natural logarithm of Precip plus 1. For this equation, R squared equals 0.48, standard error equals 14.9 inches/mi, and data points equal 76.