U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000


Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

FHWA Home / Highways for LIFE / Technology Partnerships / Safety Product Performance Evaluations / Evaluation of The TAPCO Sequential Dynamic Curve Warning System

Evaluation of The TAPCO Sequential Dynamic Curve Warning System

APPENDIX B. SITE DATA TABLES AND FIGURES

In this appendix are the data tables and figures for each site. Each curve has three tables and two figures representing the data collected during the "before" and "1 month after" periods. The first two tables are the speed statistics collected at the PC and CC. The statistics compare the before data to 1 month after, with a negative change representing a reduction. The fraction of vehicles exceeding the speed limit change shows a percentage change in the vehicles exceeding the speed limit between the data collection periods. Also in those tables are speed statistics using the tracking methodology described in the literature review. The third table contains the statistics collected from the tracking methodology and shows the speed reductions that occurred from upstream to the respective point in the curve.

The figures are graphical representations of the data shown in the tables. One figure shows the vehicles mean and 85th percentile speeds at the data collection points, while the other figure shows the change in vehicles exceeding the speed limit at the data collection points.

Iowa Highway 144

Table 8. Results for Iowa – Hwy 144 at PC.
  Before 1 Month Change
ADT 1435 1408 -27
Sample 717 708
Upstream Mean Speed 60.0 58.9 -1.1
Mean Speed 50.7 49.2 -1.5
Standard Deviation 5.2 5.8
85th Percentile Speed 56 55 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.61 0.49 -19.7%
Percentage of Vehicles 10+ Over Limit 0.24 0.16 -33.3%
Percentage of Vehicles 15+ Over Limit 0.04 0.04 0.0%
Percentage of Vehicles 20+ Over Limit 0.00 0.01 0.0%
Tracking Data
Sample 705 700
Upstream Mean Speed 60.0 59.1 -0.9
Mean Speed 50.7 49.3 -1.4
Standard Deviation 5.2 5.5
85th Percentile Speed 56 55 -1
Table 9. Results for Iowa – Hwy 144 at CC.
  Before 1 Month Change
ADT 1468 1428 -40
Sample 718 713  
Upstream Mean Speed 60.0 58.9 -1.1
Mean Speed 48 45.9 -2.1
Standard Deviation 6.2 6.3
85th Percentile Speed 53 51 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.42 0.26 -38.1%
Percentage of Vehicles 10+ Over Limit 0.12 0.05 -58.3%
Percentage of Vehicles 15+ Over Limit 0.01 0.01 0.0%
Percentage of Vehicles 20+ Over Limit 0.00 0.00 0.0%
Tracking Data
Sample 705 700
Upstream Mean Speed 60.0 59.1 -0.9
Mean Speed 48.3 46.0 -2.3
Standard Deviation 5.6 6  
85th Percentile Speed 53 51 -2
Table 10. Speed Reduction for Iowa – Hwy 144.
  Before 1 Month Change
Mean Speed Reduction Upstream to PC 9 9.7 0.5
Mean Speed Reduction Upstream to CC 11.7 13.0 1.3
Mean Speed Reduction PC to CC 2.5 3.3 0.8
85th Percentile Speed Reduction Upstream to PC 14 15 1
85th Percentile Speed Reduction Upstream to CC 17 18 1
85th Percentile Speed Reduction PC to CC 5 5 0

Iowa (Hwy 144)

an image that shows Iowa Highway 144 curve warning arrow with 45 mile per hour curve advisory speed Graph: Iowa Highway 144 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (45 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 45. Graph. Impact on vehicle speed – Iowa Hwy 144.

Map: Location of sign for southbound traffic on Iowa Highway 144 Bar chart: Change in upstream percentile vehicle speeds on Iowa Highway 144 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Iowa Highway 144 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Iowa Highway 144 at 1 month

Figure 46. Map and graphs. Location and change in percentile vehicle speed – Iowa Hwy 144.

Missouri Highway 221

Table 11. Results for Missouri – Hwy 221 at PC
  Before 1 Month Change
ADT 5277 5158 -119
Sample 2566 2523  
Upstream Mean Speed 52.2 52.8 0.6
Mean Speed 51.7 50.2 -1.5
Standard Deviation 4.7 4.8  
85th Percentile Speed 56 55 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.94 0.88 -6.4%
Percentage of Vehicles 10+ Over Limit 0.70 0.58 -17.1%
Percentage of Vehicles 15+ Over Limit 0.25 0.17 -32.0%
Percentage of Vehicles 20+ Over Limit 0.04 0.02 -50.0%
Tracking Data
Sample 2501 2459  
Upstream Mean Speed 52.2 52.8 0.6
Mean Speed 51.7 50.2 -1.5
Standard Deviation 4.7 4.8  
85th Percentile Speed 57 55 -2
Table 12. Results for Missouri – Hwy 221 at CC.
  Before 1 Month Change
ADT 5274 5169 -105
Sample 2559 2522  
Upstream Mean Speed 52.2 52.8 0.6
Mean Speed 48.3 48.6 0.3
Standard Deviation 4.4 4.6  
85th Percentile Speed 53 53 0
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.82 0.82 0.0%
Percentage of Vehicles 10+ Over Limit 0.38 0.42 10.5%
Percentage of Vehicles 15+ Over Limit 0.07 0.09 28.6%
Percentage of Vehicles 20+ Over Limit 0.01 0.01 0.0%
Tracking Data
Sample 2501 2459  
Upstream Mean Speed 52.2 52.8 0.6
Mean Speed 48.3 48.6 0.3
Standard Deviation 4.4 4.6  
85th Percentile Speed 53 53 0
Table 13. Speed reduction for Missouri – Hwy 221.
  Before 1 Month Change
Mean Speed Reduction Upstream to PC

0.6

2.6

2

Mean Speed Reduction Upstream to CC

3.9

4.3

0.4

Mean Speed Reduction PC to CC

3.4

1.7

-1.7

85th Percentile Speed Reduction Upstream to PC

3

6

3

85th Percentile Speed Reduction Upstream to CC

7

8

1

85th Percentile Speed Reduction PC to CC

5

3

-2

Missouri (Hwy 221)

Image -  Missouri Highway 221 curve site
          Graph: Missouri Highway 221 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (40 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 47. Graph. Impact on vehicle speed – Missouri Hwy 221.

Map - Location of sign for northbound traffic on Missouri Highway 221 Bar chart: Change in upstream percentile vehicle speeds on Missouri Highway 221 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Missouri Highway 221 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Missouri Highway 221 at 1 month

Figure 48. Map and graphs. Location and change in percentile vehicle speed – Missouri Hwy 221.

Washington SR 7

Table 14. Results for Washington – SR 7 at PC.
  Before 1 Month Change
ADT 1408 1413 5
Sample 763 766
Upstream Mean Speed 42.5 40.5 -2.0
Mean Speed 33.1 30.3 -2.8
Standard Deviation 4.7 4.6  
85th Percentile Speed 33 30 -3
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.96 0.89 -7.3%
Percentage of Vehicles 10+ Over Limit 0.80 0.56 -30.0%
Percentage of Vehicles 15+ Over Limit 0.37 0.18 -51.4%
Percentage of Vehicles 20+ Over Limit 0.09 0.02 -77.8%
Sample 716 733  
Tracking Data
Upstream Mean Speed 42.6 40.8 -1.8
Mean Speed 33.3 30.5 -2.8
Standard Deviation 4.6 4.4
85th Percentile Speed 38 35 -3
Table 15. Results for Washington – SR 7 at CC.
  Before 1 Month Change
ADT 1420 1444 24
Sample 750 770
Upstream Mean Speed 42.5 40.5 -2.0
Mean Speed 27.2 25.8 -1.4
Standard Deviation 2.9 3.3  
85th Percentile Speed 30 29 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.84 0.68 -19.0%
Percentage of Vehicles 10+ Over Limit 0.20 0.11 -45.0%
Percentage of Vehicles 15+ Over Limit 0.01 0.01 0.0%
Percentage of Vehicles 20+ Over Limit 0.00 0.00 0.0%
Tracking Data
Sample 716 733  
Upstream Mean Speed 42.6 40.8 -1.8
Mean Speed 27.2 26.0 -1.2
Standard Deviation 2.8 3.1  
85th Percentile Speed 30 29 -1
Table 16. Speed reduction for Washington – SR 7.
  Before 1 Month Change

Mean Speed Reduction Upstream to PC

9.3 10.3 1
Mean Speed Reduction Upstream to CC 15.4 14.8 -0.6
Mean Speed Reduction PC to CC 6.1 4.5 -1.6
85th Percentile Speed Reduction Upstream to PC 14 15.2 1.2
85th Percentile Speed Reduction Upstream to CC 20 21 1
85th Percentile Speed Reduction PC to CC 9 7 -2

Washington (SR 7)

Graph - Washington State Route 7 impact on mean and 85th percentile speeds for upstream (50 mile per hour speed limit), point of curvature (20 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 49. Graph. Impact on vehicle speed – Washington SR 7.

Washington (SR 7)

Map: Location of sign for southbound traffic on Washington State Route 7 Bar chart: Change in upstream percentile vehicle speeds on Washington State Route 7 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Washington State Route 7 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Washington State Route 7 at 1 month

Figure 50. Map and graphs. Location and change in percentile vehicle speed – Washington SR 7.

Washington SR 9

Table 17. Results for Washington – SR 9 at PC.
  Before 1 Month Change
ADT 5533 6212 679
Sample 2702 3062
Upstream Mean Speed 46.9 48.7 1.8
Mean Speed 41 39.6 -1.4
Standard Deviation 5.0 5.0
85th Percentile Speed 46 45.0 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.23 0.16 -30.4%
Percentage of Vehicles 10+ Over Limit 0.04 0.02 -50.0%
Percentage of Vehicles 15+ Over Limit 0.01 0.00 -100.0%
Percentage of Vehicles 20+ Over Limit 0.00 0.00 0.0%
Tracking Data
Sample 2598 2957
Upstream Mean Speed 47.1 48.8 1.7
Mean Speed 41.1 39.7 -1.4
Standard Deviation 4.9 4.9
85th Percentile Speed 46 44 -2
Table 18. Results for Washington – SR 9 at CC.
  Before 1 Month Change
ADT 5523 6227 704
Sample 2688 3081  
Upstream Mean Speed 46.9 48.7 1.8
Mean Speed 40.2 39.3 -0.9
Standard Deviation 5.0 5.0  
85th Percentile Speed 45 44 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.19 0.14 -26.3%
Percentage of Vehicles 10+ Over Limit 0.03 0.02 -33.3%
Percentage of Vehicles 15+ Over Limit 0.00 0.00 0.0%
Percentage of Vehicles 20+ Over Limit 0.00 0.00 0.0%
Tracking Data
Sample 2598 2957  
Upstream Mean Speed 47.1 48.8 1.7
Mean Speed 40.3 39.3 -1
Standard Deviation 5.0 4.9  
85th Percentile Speed 45 44 -1
Table 19. Speed reduction for Washington – SR 9
  Before 1 Month Change
Mean Speed Reduction Upstream to PC 6.0 9.1 3.1
Mean Speed Reduction Upstream to CC 6.8 9.5 2.7
Mean Speed Reduction PC to CC 0.8 0.4 -0.4
85th Percentile Speed Reduction Upstream to PC 9 13 4
85th Percentile Speed Reduction Upstream to CC 10 13 3
85th Percentile Speed Reduction PC to CC 2 1 -1

Washington (SR 9)

Image - Washington State Route 9 curve site
          Graph: Washington State Route 9 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (40 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 51. Graph. Impact on vehicle speed – Washington SR 9

Washington (SR 9)

Map: Location of sign for southbound traffic on Washington State Route 9 Bar chart: Change in upstream percentile vehicle speeds on Washington State Route 9 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Washington State Route 9 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Washington State Route 9 at 1 month

Figure 52. Map and graphs. Location and change in percentile vehicle speed – Washington SR 9.

Washington SR 203

Table 20. Results for Washington – SR 203 at PC
  Before 1 Month Change
ADT 10088 10761 673
Sample 4901 5190
Upstream Mean Speed 53.8 54.2 0.4
Mean Speed 53.5 51.5 -2.0
Standard Deviation 5.0 4.5
85th Percentile Speed 58 56 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.96 0.94 -2.1%
Percentage of Vehicles 10+ Over Limit 0.83 0.71 -14.5%
Percentage of Vehicles 15+ Over Limit 0.43 0.23 -46.5%
Percentage of Vehicles 20+ Over Limit 0.08 0.03 -62.5%
Tracking Data
Sample 4637 4902
Upstream Mean Speed 54.1 54.4 0.3
Mean Speed 53.6 51.6 -2
Standard Deviation 4.7 4.5
85th Percentile Speed 58 56 -2
Table 21. Results for Washington – SR 203 at CC
  Before 1 Month Change
ADT 10120 10756 636
Sample 4921 5148
Upstream Mean Speed 53.8 54.2 0.4
Mean Speed 51.6 51.5 -0.1
Standard Deviation 4.6 4.6
85th Percentile Speed 56 56 0
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.94 0.94 0.0%
Percentage of Vehicles 10+ Over Limit 0.72 0.70 -2.8%
Percentage of Vehicles 15+ Over Limit 0.25 0.24 -4.0%
Percentage of Vehicles 20+ Over Limit 0.03 0.03 0.0%
Tracking Data
Sample 4637 4902
Upstream Mean Speed 54.1 54.4 0.3
Mean Speed 51.8 51.6 -0.2
Standard Deviation 4.5 4.6
85th Percentile Speed 56 56 0
Table 22. Speed reduction for Washington – SR 203.
  Before 1 Month Change
Mean Speed Reduction Upstream to PC 0.5 2.8 2.3
Mean Speed Reduction Upstream to CC 2.4 2.8 0.4
Mean Speed Reduction PC to CC 1.8 0 -1.8
85th Percentile Speed Reduction Upstream to PC 3 6 3
85th Percentile Speed Reduction Upstream to CC 6 7 1
85th Percentile Speed Reduction PC to CC 3 2 -1

Washington (SR 203)

Image: Washington State Route 203 curve site Graph: Washington State Route 203 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (no curve advisory speed), and center of curve before implementation and 1 month after

Figure 53. Graph Impact on vehicle speed – Washington SR 203.

Washington (SR 203)

Map: Location of sign for southbound traffic on Washington State Route 203 Bar chart: Change in upstream percentile vehicle speeds on Washington State Route 203 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Washington State Route 203 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Washington State Route 203 at 1 month

Figure 54. Map and graphs. Location and change in percentile vehicle speed – Washington SR 203.

Wisconsin Highway 20

Table 23. Results for Wisconsin – Hwy 20 at PC
  Before 1 Month Change
ADT 3583 3250 -333
Sample 1692 1556
Upstream Mean Speed 53.7 55.2 1.5
Mean Speed 39.6 37.8 -1.8
Standard Deviation 7.6 7.1
85th Percentile Speed 47 45 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.77 0.70 -9.1%
Percentage of Vehicles 10+ Over Limit 0.58 0.47 -19.0%
Percentage of Vehicles 15+ Over Limit 0.27 0.16 -40.7%
Percentage of Vehicles 20+ Over Limit 0.07 0.03 -57.1%
Tracking Data
Sample 1318 1251
Upstream Mean Speed 54.1 55.7 1.6
Mean Speed 42.1 40.1 -2
Standard Deviation 5.7 5.4
85th Percentile Speed 48 45 -3
Table 24. Results for Wisconsin – Hwy 20 at CC
  Before 1 Month Change
ADT 3128 2823 -305
Sample 1456 1350
Upstream Mean Speed 53.7 55.2 1.5
Mean Speed 37.4 35.6 -1.8
Standard Deviation 4.8 4.6
85th Percentile Speed 42 40 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.77 0.63 -18.2%
Percentage of Vehicles 10+ Over Limit 0.33 0.18 -45.5%
Percentage of Vehicles 15+ Over Limit 0.06 0.02 -66.7%
Percentage of Vehicles 20+ Over Limit 0.01 0.00 -100.0%
Tracking Data
Sample 1318 1251
Upstream Mean Speed 54.1 55.7 1.6
Mean Speed 37.8 36.1 -1.7
Standard Deviation 4.4 4.1
85th Percentile Speed 42 40 -2
Table 25. Speed reduction for Wisconsin – Hwy 20
  Before 1 Month Change
Mean Speed Reduction Upstream to PC 12.0 15.6 3.6
Mean Speed Reduction Upstream to CC 16.2 19.5 3.3
Mean Speed Reduction PC to CC 4.3 4.0 -0.3
85th Percentile Speed Reduction Upstream to PC 18 20 2
85th Percentile Speed Reduction Upstream to CC 23 25 2
85th Percentile Speed Reduction PC to CC 8 7 -1

Wisconsin (Hwy 20)

Image: Wisconsin Highway 20 curve site Graph: Wisconsin Highway 20 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (30 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 55. Graph. Impact on vehicle speed – Wisconsin Hwy 20.

Wisconsin (Hwy 20)

Map: Location of sign for eastbound traffic on Wisconsin Highway 20 Bar chart: Change in upstream percentile vehicle speeds on Wisconsin Highway 20 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Wisconsin Highway 20 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Wisconsin Highway 20 at 1 month

Figure 56. Map and graphs. Location and change in percentile vehicle speed – Wisconsin Hwy 20.

Wisconsin Highway 67

Table 26. Results for Wisconsini – Hwy 67 at PC.
  Before 1 Month Change
ADT 3494 4018 524
Sample 1726 1992  
Upstream Mean Speed 50.0 48.9 -1.1
Mean Speed 46.1 44.5 -1.6
Standard Deviation 5.9 6  
85th Percentile Speed 52 51 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.99 0.99 0.0%
Percentage of Vehicles 10+ Over Limit 0.97 0.94 -3.1%
Percentage of Vehicles 15+ Over Limit 0.87 0.80 -8.0%
Percentage of Vehicles 20+ Over Limit 0.65 0.51 -21.5%
Tracking Data
Sample 1668 1931  
Upstream Mean Speed 50.0 48.9 -1.1
Mean Speed 46.1 44.5 -1.6
Standard Deviation 5.8 6.0  
85th Percentile Speed 52 51 -1
Table 27. Results for Wisconsin – Hwy 67 at CC.
  Before 1 Month Change
ADT 3496 4004 508
Sample 1713 1979  
Upstream Mean Speed 50.0 48.9 -1.1
Mean Speed 39.7 37.9 -1.8
Standard Deviation 5.0 5.0  
85th Percentile Speed 45 43 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.97 0.95 -2.1%
Percentage of Vehicles 10+ Over Limit 0.86 0.76 -11.6%
Percentage of Vehicles 15+ Over Limit 0.53 0.38 -28.3%
Percentage of Vehicles 20+ Over Limit 0.15 0.08 -46.7%
Tracking Data
Sample 1668 1931  
Upstream Mean Speed 50.0 48.9 -1.1
Mean Speed 39.7 37.9 -1.8
Standard Deviation 5.0 5.0  
85th Percentile Speed 45 43 -2
Table 28. Speed Reduction for Wisconsin – Hwy 67.
  Before 1 Month Change
Mean Speed Reduction Upstream to PC 3.9 4.40 0.5
Mean Speed Reduction Upstream to CC 10.2 11.0 0.8
Mean Speed Reduction PC to CC 6.4 6.6 0.2
85th Percentile Speed Reduction Upstream to PC 11 13 2
85th Percentile Speed Reduction Upstream to CC 19 20 1
85th Percentile Speed Reduction PC to CC 9 9 0

Wisconsin (Hwy 67)

Image: Wisconsin Highway 67 curve site Graph: Wisconsin Highway 67 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (25 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 57. Graph. Impact on vehicle speed – Wisconsin Hwy 67

Wisconsin (Hwy 67)

Map: Location of sign for southbound traffic on Wisconsin Highway 67 Bar chart: Change in upstream percentile vehicle speeds on Wisconsin Highway 67 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Wisconsin Highway 67 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Wisconsin Highway 67 at 1 month

Figure 58. Map and graphs. Location and change in percentile vehicle speed - Wisconsin.

Wisconsin Highway 213

Table 29. Results for Wisconsin – Hwy 213 at PC.
  Before 1 Month Change
ADT 2369 2249 -120
Sample 1156 1119  
Upstream Mean Speed 58.8 59.8 1.0
Mean Speed 55.3 54.6 -0.7
Standard Deviation 7 6.6  
85th Percentile Speed 61 61 0
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.63 0.57 -9.5%
Percentage of Vehicles 10+ Over Limit 0.28 0.21 -25.0%
Percentage of Vehicles 15+ Over Limit 0.03 0.03 0.0%
Percentage of Vehicles 20+ Over Limit 0.00 0.00 0.0%
Tracking Data
Sample 1134 1098  
Upstream Mean Speed 58.9 59.9 1
Mean Speed 55.5 54.8 -0.7
Standard Deviation 6.5 6.2  
85th Percentile Speed 61 61 0
Table 30. Results for Wisconsin – Hwy 213 at CC.
  Before 1 Month Change
ADT 2552 2428 -124
Sample 1220 1193  
Upstream Mean Speed 58.8 59.8 1.0
Mean Speed 53.2 52.2 -1.0
Standard Deviation 9.7 9.8  
85th Percentile Speed 61 60 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.59 0.52 -11.9%
Percentage of Vehicles 10+ Over Limit 0.25 0.20 -20.0%
Percentage of Vehicles 15+ Over Limit 0.02 0.03 50.0%
Percentage of Vehicles 20+ Over Limit 0.00 0.00 0.0%
Tracking Data
Sample 1134 1098  
Upstream Mean Speed 58.9 59.9 1
Mean Speed 54.7 54.0 -0.7
Standard Deviation 7.7 7.5  
85th Percentile Speed 61 61 0
Table 31. Speed reduction for Wisconsin – Hwy 213
  Before 1 Month Change
Mean Speed Reduction Upstream to PC

3.4 5.1 1.7
Mean Speed Reduction Upstream to CC 4.2 5.9 1.7
Mean Speed Reduction PC to CC 0.8 0.8 0
85th Percentile Speed Reduction Upstream to PC 9 10 1
85th Percentile Speed Reduction Upstream to CC 10 11.5 1.5
85th Percentile Speed Reduction PC to CC 2 2 0

Wisconsin (Hwy 213)

Image - Wisconsin Highway 213 curve site
        Graph: Wisconsin Highway 213 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (50 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 59. Graph. Impact on vehicle speed – Wisconsin Hwy 213.

Wisconsin (Hwy 213)

Map: Location of sign for eastbound traffic on Wisconsin Highway 213 Bar chart: Change in upstream percentile vehicle speeds on Wisconsin Highway 213 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Wisconsin Highway 213 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Wisconsin Highway 213 at 1 month

Figure 60. Map and graphs. Location and change in percentile vehicle speed – Wisconsin Hwy 213.

Texas FM 109

Table 32. Results for Texas – FM 109 at PC.
  Before 1 Month Change
ADT 2187 2031 -156
Sample 1036 954  
Upstream Mean Speed 58.2 59.6 1.4
Mean Speed 46.6 45.8 -0.8
Standard Deviation 5.7 5.4  
85th Percentile Speed 52 51 -1
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.92 0.90 -2.2%
Percentage of Vehicles 10+ Over Limit 0.68 0.62 -8.8%
Percentage of Vehicles 15+ Over Limit 0.30 0.23 -23.3%
Percentage of Vehicles 20+ Over Limit 0.07 0.04 0.0%
Table 33. Results for Texas – FM 109 at CC.
  Before 1 Month Change
ADT 2129  1991 -138
Sample 1017  938  
Upstream Mean Speed 58.2 59.6 1.4
Mean Speed 45.2  43.8 -1.4
Standard Deviation 5.2  4.7  
85th Percentile Speed 50  48 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.90  0.85 -5.7%
Percentage of Vehicles 10+ Over Limit 0.60  0.43 -27.7%
Percentage of Vehicles 15+ Over Limit 0.18  0.09 -51.4%
Percentage of Vehicles 20+ Over Limit 0.02  0.01 0.0%

Texas (FM 109)

Graph: Texas FM 109 impact on mean and 85th percentile speeds for upstream (60 mile per hour speed limit), point of curvature (35 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 61. Graph. Impact on vehicle speed – Texas FM 109

Texas (FM 109)

Map: Location of sign for northbound traffic on Texas FM 109 Bar chart: Change in upstream percentile vehicle speeds on Texas FM 109 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Texas FM 109 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Texas FM 109 at 1 month

Figure 62. Map and graphs. Location and change in percentile vehicle speed – Texas FM 109.

Texas FM 407

Table 34. Results for Texas – FM 407 at PC
  Before 1 Month Change
ADT 2480 2883 403
Sample 856 1443  
Upstream Mean Speed 61.3 60.1 -1.2
Mean Speed 51.5 49.7 -1.8
Standard Deviation 5.6 5.3  
85th Percentile Speed 57 55 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.89 0.83 -6.7%
Percentage of Vehicles 10+ Over Limit 0.67 0.53 -20.9%
Percentage of Vehicles 15+ Over Limit 0.31 0.18 -41.9%
Percentage of Vehicles 20+ Over Limit 0.06 0.03 0.0%
*Note: Only 18 hours of data collected because of puncture in the tube
Table 35. Results for Texas – FM 407 at CC.
  Before 1 Month Change
ADT 2238 2885 647
Sample 579 1446  
Upstream Mean Speed 61.3 60.1 -1.2
Mean Speed 47.3 46.2 -1.1
Standard Deviation 6.3 5.6  
85th Percentile Speed 53 51 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.73 0.67 -8.2%
Percentage of Vehicles 10+ Over Limit 0.37 0.26 -29.7%
Percentage of Vehicles 15+ Over Limit 0.10 0.04 -60.0%
Percentage of Vehicles 20+ Over Limit 0.01 0.01 0.0%
*Note: Only 16 hours of data collected because of puncture in the tube

Texas (FM 407)

Graph: Texas FM 407 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (40 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 63. Graph. Impact on vehicle speed – Texas FM 407.

Texas (FM 407)

Map - Location of sign for eastbound traffic on Texas FM 407. Bar chart - Change in upstream percentile vehicle speeds on Texas FM 407at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Texas FM 407at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Texas FM 407at 1 month

Figure 64. Map and graphs. Location and change in percentile vehicle speed – Texas FM 407.

Texas FM 530

Table 36. Results for Texas – FM 530 at PC.
  Before 1 Month Change
ADT 675 418 -257
Sample 71 200  
Upstream Mean Speed 62.1 60.0 -2.1
Mean Speed 47.1 46.2 -0.9
Standard Deviation 9.3 6.3  
85th Percentile Speed 55 53 -2
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.86 0.88 2.3%
Percentage of Vehicles 10+ Over Limit 0.77 0.62 -19.5%
Percentage of Vehicles 15+ Over Limit 0.38 0.33 -13.2%
Percentage of Vehicles 20+ Over Limit 0.20 0.09 0.0%
*Note: The “before” count had many unknown counts, leading to fewer counts for the 24-hour period
Table 37. Results for Texas – FM 530 at CC.
  Before 1 Month Change
ADT 488 430 -58
Sample 237 204  
Upstream Mean Speed 62.1 60.0 -2.1
Mean Speed 43.2 41.2 -2.0
Standard Deviation 6.1 5.2  
85th Percentile Speed 48.6 46 -2.6
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.79 0.63 -20.3%
Percentage of Vehicles 10+ Over Limit 0.44 0.28 -36.4%
Percentage of Vehicles 15+ Over Limit 0.11 0.04 -63.6%
Percentage of Vehicles 20+ Over Limit 0.02 0.00 0.0%

Texas (FM 530)

Graph: Texas FM 530 impact on mean and 85th percentile speeds for upstream (60 mile per hour speed limit), point of curvature (35 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 65. Graph. Impact on vehicle speed – Texas FM 530

Texas (FM 530)

Map: Location of sign for westbound traffic on Texas FM 530 Bar chart: Change in upstream percentile vehicle speeds on Texas FM 530 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Texas FM 530 at 1 month. Bar chart: Change in center of curvature percentile vehicle speeds on Texas FM 530 at 1 month

Figure 66. Map and graphs. Location and change in percentile vehicle speed – Texas FM 530.

Texas FM 1148

Table 38. Results for Texas – FM 1148 at PC.
  Before 1 Month Change
ADT 3549 3742 193
Sample 1746 1832  
Upstream Mean Speed 59.3 58.9 -0.4
Mean Speed 51.9 49.5 -2.4
Standard Deviation 5 4.8  
85th Percentile Speed 57 54 -3
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.94 0.86 -8.5%
Percentage of Vehicles 10+ Over Limit 0.70 0.51 -27.1%
Percentage of Vehicles 15+ Over Limit 0.28 0.13 -53.6%
Percentage of Vehicles 20+ Over Limit 0.06 0.02 0.0%
Table 39. Results for Texas – FM 1148 at CC.
  Before 1 Month Change
ADT 3538 3708 170
Sample 1748 1831  
Upstream Mean Speed 59.3 58.9 -0.4
Mean Speed 48.5 48.4 -0.1
Standard Deviation 4.5 4.9  
85th Percentile Speed 53 53 0
Fraction of vehicles exceeding advisory speed
Percentage of Vehicles 5+ Over Limit 0.83 0.79 -4.8%
Percentage of Vehicles 10+ Over Limit 0.40 0.41 2.5%
Percentage of Vehicles 15+ Over Limit 0.08 0.08 0.0%
Percentage of Vehicles 20+ Over Limit 0.01 0.01 0.0%

Texas (FM 1148)

Graph: Texas FM 1148 impact on mean and 85th percentile speeds for upstream (55 mile per hour speed limit), point of curvature (40 mile per hour advisory speed), and center of curve before implementation and 1 month after

Figure 67. Graph. Impact on vehicle speed – Texas FM 1148

Texas (FM 1148)

Map: Location of sign for northbound traffic on Texas FM 1148
          Bar chart: Change in upstream percentile vehicle speeds on Texas FM 1148 at 1 month Bar chart: Change in point of curvature percentile vehicle speeds on Texas FM 1148 at 1 month Bar chart: Change in center of curvature percentile vehicle speeds on Texas FM 1148 at 1 month

Figure 68. Map and graphs. Location and change in percentile vehicle speed – Texas FM 1148

Page last modified on June 23, 2016
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000