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HERS-ST Highway Economic Requirements System - State Version: Technical Report

Appendix E Operating Cost Equations

Vehicle operating cost equations are disaggregated by vehicle type (small auto, medium/large auto, 4-tire trucks, 6-tire trucks, 3+ axle single-unit trucks, 3-4 axle combination trucks, and 5+ axle combination trucks) and by cost component (fuel, oil, tires, maintenance, and depreciation), under constant speed conditions. Also, additional operating costs due to speed variability are provided for all seven vehicle types and all five cost components, and additional operating costs due to horizontal curvature are provided for all seven vehicle types for three of the cost components (fuel, tire wear, and maintenance). Finally, a set of pavement condition adjustment factors to constant-speed operating costs are generated for each of the five cost components (fuel and oil are combined in one equation) as functions of pavement surface quality (PSR).

E.1 Sources of HERS Operating Cost Equations

The computations for the operating cost components in HERS are based on the report "Vehicle Operating Costs, Fuel Consumption, and Pavement Type and Condition Factors", by J.P. Zaniewski, et. al., Texas Research and Development Foundation, June 1982. This report was prepared for the U. S. Department of Transportation, Federal Highways Administration.

In the Zaniewski report, operating costs are listed in tables in Appendix B. There are three categories of tables matching the HERS categories: constant-speed operating costs; excess cost due to speed change cycles; and excess costs due to horizontal curvature. The Zaniewski tables for constant-speed operating costs are given as a matrix of speed in miles per hour and gradient. The miles per hour are given from 5 to 70 in increments of 5-m.p.h. The gradient is given from 8% to 8% in increments of 1%.

The tables for excess cost due to horizontal curvature are organized as a matrix of degrees of curvature (1°, 2° 6°, 8°, 10° 20°, 25°, 30°) and speed in miles per hour (5 to 70 in 5-m.p.h. increments).

The Zaniewski data were scanned and converted to spreadsheet form. Some corrections were applied where it appeared that the original data were misleading. In two cases, data from the Zaniewski report demonstrated constant-speed fuel consumption of 0.0 over a broad range of gradient and speed. In these cases, data from alternate sources were used in place of the Zaniewski data. These sources were P. J. Claffey and Associates, "Running Costs of Motor Vehicles as Affected by Road Design and Traffic," NCHRP Report 111, Highway Research Board, National Research Council, Division of Engineering, 1971; and Daniels, C. Vehicle Operating Costs in Transportation Studies, E.S.U Technical Series No. 1, London: Spencer House, 1974. Both these sources were referenced by the Zaniewski report.

E.1.1 Region of Interest

For constant-speed operating costs, the data between gradients of 3% and 3% (inclusive) are considered important. Speeds of up to 90 miles per hour are also important, and are extrapolated from existing data. Data for speeds of 2 miles per hour are also extrapolated.

For excess cost due to curvature, only speed/curvature settings below the value of VCURVE (Equation 5.39) are considered important. In some cases, at a low degree of curvature, data must be extrapolated to 90-m.p.h.

E.1.2 Updating of Operating Cost Equations

An analysis of the operating cost equations of the December 2000 version of HERS revealed discontinuities within some of the equations. As a result, many of the operating cost equations have been revised to provide better accuracy and to eliminate the discontinuities within the constant-speed operating cost equations. The equations for excess cost due to curvature were updated as well to establish complete coverage of the equations, thus eliminating the practice of interpolating values obtained from a look-up table.

Table E-1 displays the complete array of operating cost equations, and indicates which constant-speed and excess cost due to curvature equations were updated.

E.1.2.1 Determining Which Equations Required Updating

Existing constant-speed operating costs equations were examined graphically within the region of interest (3% to 3% gradient, 2-90 m.p.h.) to look for discontinuity or other forms of error (e.g. values less than 0; arcing towards infinity, especially in the extremes). The results were also compared, graphically, to the source data. If the results show a noticeable discontinuity or a poor resemblance to the source data, then the equations for that component were updated. The graphical examination used gradient increments of 0.25% between the range of 3% to 3%, and increments of 1- m.p.h. between 2- and 90-m.p.h. Gradient ranges of between 8% to 3% and 3% to 8% were also examined for erratic behavior, though this examination was not as exacting as within the region of interest.

In the case of excess operating costs due to curvature, the previously equations applied to cases of speeds of greater than or equal to 55-m.p.h. New equations were generated for the complete region of interest.

E.1.2.2 Method and Tools Employed

Microsoft Excel was used for graphic display of the data to examine for discontinuity and to compare, graphically, against the original data. Curves were also segmented or re-segmented in spreadsheets (different equations may be used for different portions of the speed or gradient, and segmentation may have been increased or, more often, simplified).

Data from the spreadsheets were then read by a software package called ‘TableCurve 3D', by SPSS. TableCurve produces a list of equations to predict the output based on the two input variables (gradient and speed). The equations are ranked by adjusted r2 score. The first pass attempts to find a reasonable fit with a maximum of five terms. If a good fit is not found, then the term count is stepped until either a reasonable fit is found or that it becomes apparent that resegmenting is necessary. Final equations were tested for continuity and conformity to the original data.

Table E-1. Equation Update Summary
Component Vehicle Type
Small Auto Med/Large Auto 4-Tire Truck 6-Tire Truck 3+ Axle Single-Unit Truck 3-4 Axle Combo Unit Truck 5+ Axle Combo Unit Truck
= equation updated
Constant-Speed Fuel Consumption
Constant-Speed Oil Consumption
Constant-Speed Tire Wear
Constant-Speed Maintenance and Repair
Constant-Speed Depreciation
Speed Variability Fuel Consumption
Speed Variability Oil Consumption
Speed Variability Tire Wear
Speed Variability Maintenance and Repair
Speed Variability Depreciation
Curvature Fuel Consumption
Curvature Tire Wear
Curvature Maintenance and Repair
E.1.2.3 Notable Exception: 3-4 Axle Combination Unit Trucks

For reasons noted above, the data from the Zaniewski report were not used directly for constant-speed fuel consumption (CSFC) for 3-4 axle combination unit trucks and 5+ axle combination unit trucks. Data from the Claffey study, adjusted to scale, were used for 3-4 axle CU trucks. It should be noted that the Zaniewski data are consistent with the Claffey data at steep uphill gradients (GR 3) across the range of speed, and at lesser gradients up to 30 m.p.h.

E.1.2.4 Notable Exception: 5+ Axle Combination Unit Trucks

The Zaniewski report states that the data for 3-S2 semi (5+ axle CU) trucks were extrapolated from 2-S2 semi (3+ axle CU) trucks, yet the report does not state the method applied for this extrapolation. For the HERS equations, the following method was applied to obtain constant-speed fuel consumption equations for 5+ axle CU trucks:

  • The percentage difference of fuel consumption rates from 2-S2 semi (3-4 Axle CU truck) and 3-S2 semi (5+ axle CU truck) from the Zaniewski report was derived for all gradient/speed points.
  • The average percentage difference for each gradient was then generated. For gradients less than (1), where the data becomes zero for both vehicle types, the percentage difference from gradient of (1) is used. This created an asymptote on the consumption curve as the gradient gets steeper downhill, consistent with both the Claffey and Daniels findings.
  • The 3-4 axle CU truck CSFC data (generated from Claffey) were incremented by the average percentage differences, along gradients, from the Zaniewski report, to create CSFC data points for 5+ axle CU trucks.

The new data tables for both 3-4 Axle CU trucks and 5+ axle CU trucks were then rendered using Microsoft Excel and processed using TableCurve, as shown above.

E.2 The Operating Cost Equations

The equations below are grouped by vehicle type, then by component. Equations are typically segmented, and the conditions to define the range of the segments are given along with the equation for that segment. The tables are presented in the following order:

Within each vehicle type, equations are presented in the order shown in Table E-1.

The list below gives the variable names used in the equations:

AES = average effective speed
GR = grade (in percent)
CSMAX = maximum speed during speed change cycle
DCA = degrees of curvature
CSFC = constant-speed fuel consumption (gallons/1000 miles)
CSOC = constant-speed oil consumption (quarts/1000 miles)
CSTW = constant-speed tire wear (% worn/1000 miles)
CSMR = constant-speed maintenance and repair (% avg. cost/1000 miles)
CSVD = constant-speed depreciation (% new price/1000 miles)
PCAFOC = pavement condition adjustment factor for oil consumption
PCAFTW = pavement condition adjustment factor for tire wear
PCAFMR = pavement condition adjustment factor for maintenance and repair
PCAFVD = pavement condition adjustment factor for depreciation expenses
SCCFC = excess fuel consumption for speed change cycles (gallons/1000 cycles)
SCCOC = excess oil consumption for speed change cycles (quarts/1000 cycles)
SCCTW = excess tire wear for speed change cycles (% worn/1000 cycles)
SCCMR = excess maintenance and repair for speed change cycles (% average cost/1000 cycles)
SCCD = excess depreciation for speed change cycles (% new price/1000 cycles)
CFC = excess fuel consumption due to curves (gallons/1000 vehicle miles)
CTW = excess tire wear due to curves (% worn/1000 vehicle miles)
CMR = excess maintenance and repair due to curves (% average cost/1000 vehicle miles)
PSR = pavement serviceability rating

E.3 Small Automobile

E.3.1 Constant-Speed Fuel Consumption (CSFC)
Table E-2. Small Automobile Constant-Speed Fuel Consumption
1 Condition GR 0
Equation CSFC = 100.82 4.9713 × AES + 0.11148 × AES2 0.0011161 × AES3 + 5.1089e06 × AES4 + 3.0947 × GR
2 Condition GR < 0 and AES 40
Equation CSFC = (91.045 4.0552×AES + 0.060972×AES2 + 4.0504×GR + 0.4227×GR2)/(1 0.014068×AES + 0.0004774×AES20.045957×GR + 0.0054245×GR2)
3 Condition GR < 0 and AES > 40
Equation CSFC = 23.373 + 3.6374×GR + 0.21681×GR2 + (72.562/(1 + exp(((AES 81.639)/7.4605))))
E.3.2 Constant-Speed Oil Consumption (CSOC)
Table E-3. Small Automobile Constant-Speed Oil Consumption
1 Condition GR > 0 and AES < 55
Equation CSOC = exp(2.7835 0.79034×ln(AES) 1.1346/(AES(1.5)) + 0.65342×(GR(0.5)))
2 Condition GR 0 and 55 AES < 70
Equation CSOC = 170.4 + 34.02×ln(AES) + 1939/AES + 0.4747×GR 0.003296×AES×GR
3 Condition GR 0 and AES 70
Equation CSOC = 170.4 + 34.02×ln(AES) + 1939/AES+0.27×GR
4 Condition GR 0 and AES < 55
Equation CSOC = 1.0435 + (327.89/((1 + (((AES + 7.1977)/3.0141)2)) × (1 + (((GR + 8.0484)/2.8984)2))))
5 Condition Otherwise
Equation CSOC = 170.4+34.02×ln(AES)+1939/AES
E.3.3 Constant-Speed Tire Wear (CSTW)
Table E-4. Small Automobile Constant-Speed Tire Wear
1 Condition GR 2.5 and AES < 55
Equation CSTW=exp(2.55+0.0001621×AES2+0.01441×AES+1.473×ln(GR)0.001638×AES×GR)
2 Condition GR 2.5 and AES 55
Equation CSTW=1.314+0.000733×AES20.05758×AES+0.01514×GR2 +0.003997×AES×GR
3 Condition (0 < GR < 2.5 and AES < 15)
or (AES/20 < GR < 2.5 and AES 15)
Equation CSTW=0.1959+2.51×106×AES30.0352×ln(AES)+0.01754×GR2+0.00348×AES×GR
4 Condition (1.5 < GR 0 and AES < 15)
or (AES/10 < GR AES/20 and AES 15)
Equation CSTW=0.0604+2.92×108×AES4+0.0000796×AES2+0.0274×GR2+0.074×GR+0.0000568×AES2×GR
5 Condition otherwise
Equation CSTW=exp(5.390.000895×AES2+0.0962×GR+2.83×ln(GR)0.00397×AES×GR)
E.3.4 Constant-Speed Maintenance and Repair (CSMR)
Table E-5. Small Automobile Constant-Speed Maintenance and Repair
1 Condition GR 0
Equation CSMR=48.3+0.00865×AES2+0.0516×AES×GR
2 Condition (1.5 GR < 0 and AES 25)
or (GR < 0 and 25 < AES < 55 and AES 12.2×GR+4)
Equation CSMR=45.1+0.00582×AES2+0.23×AES+0.0502×AES×GR
3 Condition (GR < 1.5 and AES 25)
or (GR < 0 and 25 < AES < 55 and AES < 12.2×GR+4)
Equation CSMR = 5.830.01932×AES223.4×GR
4 Condition 0.14×AES+3.6 < GR < 0 and AES 55
Equation CSMR=73.35+0.01397×AES20.7398×AES+0.04994×AES×GR
5 Condition otherwise
Equation CSMR=4.270.0208×AES223.63×GR
E.3.5 Constant-Speed Depreciation (CSVD)
Table E-6. Small Automobile Constant-Speed Vehicle Depreciation
1 Condition all
Equation CSVD = 2.2+0.001596×AES0.38×ln(AES)
E.3.6 Excess Fuel Consumption Due to Speed Variability (SCCFC)
Table E-7. Small Automobile Excess Fuel Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCFC=0.00424×CSMAX3
2 Condition CSMAX 5
Equation SCCFC=0.04547+0.08559×CSMAX+3677×108×CSMAX3
E.3.7 Excess Oil Consumption Due to Speed Variability (SCCOC)
Table E-8. Small Automobile Excess Oil Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCOC=0.00004×CSMAX3
2 Condition CSMAX 5
Equation SCCOC=0.000879+0.000934×CSMAX1612×108×CSMAX2+193×109×CSMAX3
E.3.8 Excess Tire Wear Due to Speed Variability (SCCTW)
Table E-9. Small Automobile Excess Tire Wear Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCTW=0.0008×CSMAX2
2 Condition CSMAX 5
Equation SCCTW=exp(7.112+1.999×ln(CSMAX) 8384×108×CSMAX2)
E.3.9 Excess Maintenance and Repair Due to Speed Variability (SCCMR)
Table E-10. Small Automobile Excess Maintenance and Repair Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCMR=0.0016×CSMAX2
2 Condition CSMAX 5
Equation SCCMR=exp(6.284+0.006889×CSMAX+1.881×ln(CSMAX) 7388×108×CSMAX2)
E.3.10 Excess Depreciation Due to Speed Variability (SCCD)
Table E-11. Small Automobile Excess Depreciation Due to Speed Variability
1 Condition CSMAX < 60
Equation SCCD=0.0004×CSMAX
2 Condition CSMAX 60
Equation SCCD=exp(4.327+0.000168×CSMAX2)
E.3.11 Excess Fuel Consumption Due to Curves (CFC)
Table E-12. Small Automobile Excess Fuel Consumption Due to Curves
1 Condition AES (1/(0.001147 + 0.008062×DCA(0.5) + 0.008862/DCA))
Equation CFC = MAX(0, 18387.7115×(1/(1 + (DCA/39.459)(3.0419)))× 1/(1 + (AES/104.38)(6.2768)))
2 Condition DCA 6 and AES > 10 and AES (0.6807×DCA + 30.944)
Equation CFC = MAX(0, 0.046905 + 0.95904×LN(DCA) 0.02218×AES 0.17662×(LN(DCA))2 + 0.000957×AES2 0.021388×AES×LN(DCA))
3 Condition (DCA 6 and AES 10)
or (DCA < 6 and AES 25)
Equation CFC = MAX(0, 1.9503 + 1.0112×LN(DCA) + 0.31328×AES 0.16763×(LN(DCA))2 0.012903×AES2 0.031507×AES×LN(DCA))
4 Condition Otherwise
Equation CFC=0
E.3.12 Excess Tire Wear Due to Curves (CTW)
Table E-13. Small Automobile Excess Tire Wear Due to Curves
1 Condition (DCA16 and AES (0.031746×DCA2 + 0.74603×DCA + 21.19))
or (16 > DCA 6 and AES (45 1.9167×DCA + 0.041667×DCA2))
or (DCA < 6 and AES (442.3 + 2959.4/DCA(0.5) 6735.1/DCA + 6810.6/DCA(1.5) 2582.5/DCA2))
Equation CTW = MAX(0, 351887 × EXP(EXP((DCA 51.408)/19.756) (DCA51.408)/19.756 + 1) × EXP(EXP((AES 122.22)/38.201) (AES122.22)/38.201 + 1))
2 Condition (DCA 16 and AES < (0.031746×DCA2 +0.74603×DCA + 21.19))
or (16 > DCA 8 and AES < (45 1.9167×DCA + 0.041667×DCA2))
Equation CTW = MAX(0, 21.508 + 13.474×LN(DCA) + 19.67×LN(AES) 1.5206×(LN(DCA))2 3.5315×(LN(AES))2 3.6298×LN(DCA)×LN(AES))3
3 Condition (8 > DCA 6 and AES < (45 1.9167×DCA + 0.041667×DCA2))
or (DCA < 6 and AES < (442.3 + 2959.4/DCA(0.5) 6735.1/DCA + 6810.6/DCA(1.5) 2582.5/DCA2)
Equation CTW = MAX(0, 3.3578 + 3.5095×DCA + 0.080638×AES 0.18665×DCA20.00054297×AES2 0.061173×DCA×AES)
E.3.13 Excess Maintenance and Repair Due to Curves
Table E-14. Small Automobile Excess Maintenance and Repair Due to Curves
1 Condition (DCA > 10 and AES 0.65×DCA + 34.5)
or (DCA < 10 and AES 2.4444×DCA + 52.444)
Equation CMR = MAX(0, EXP(19.624 1.0614×DCA(0.5)×LN(DCA) + 6.4853×DCA(0.5) +0.033374×AES(1.5) 0.00046284×AES2×LN(AES)))
2 Condition 5 DCA 10 and (1×DCA + 20) AES (1×DCA + 25)
Equation CMR = 0.1
3 Condition Otherwise
Equation CMR = 0

E.4 Medium/Large Automobile

E.4.1 Constant-Speed Fuel Consumption (CSFC)
Table E-15. Medium/Large Automobile Constant-Speed Fuel Consumption
1 Condition AES 40
Equation CSFC = 88.556 3.384×AES + 1.7375×GR + 0.053161×AES2 + 0.18052×GR2 + 0.076354×AES×GR
2 Condition AES > 40
Equation CSFC = 85.255 2.2399×AES + 2.7478×GR + 0.028615×AES2 + 0.041389×GR2 + 0.046242×AES×GR
E.4.2 Constant-Speed Oil Consumption (CSOC)
Table E-16. Medium/Large Automobile Constant-Speed Oil Consumption
1 Condition GR > 0 and AES < 55
Equation CSOC = exp(1.5698 + 9.8768/AES(0.5) 7.6187 /AES + 0.70702×GR(0.5))
2 Condition GR 0 and 55 AES < 70
Equation CSOC = 9.52340.29873×AES +0.0026913×AES2 + 0.28997×GR1.00129
3 Condition GR 0 and AES 70
Equation CSOC = 173.3 + 34.6×ln(AES) + 1973/AES + 0.29×GR
4 Condition 3 GR 0 and 15 AES < 55
Equation CSOC = 0.42295 + 0.35839×AES 0.029984×AES2 + 0.0010392×AES3 0.000016196×AES4 + 9.3539e08×AES5 0.0024×GR
5 Condition GR < 3 and 15 AES < 55
Equation CSOC = 1/(0.18739 + 0.0014953×AES(1.5) 1.7461/GR)
6 Condition GR 0 and AES < 15
Equation CSOC = exp(1.7713 0.12178×AES(0.5)×ln(AES) + 0.14636×GR + 0.11002×GR2 + 0.0082804×GR3)
7 Condition Otherwise
Equation CSOC = 173.3 + 34.6×ln(AES) + 1973/AES
E.4.3 Constant-Speed Tire Wear (CSTW)
Table E-17. Medium/Large Automobile Constant-Speed Tire Wear
1 Condition GR 2.5 and AES < 55
Equation CSTW=exp(2.39+0.0001564×AES2+0.01367×AES+1.475×ln(GR)0.001586×AES×GR)
2 Condition (0 < GR < 2.5 and AES < 15)
or (AES/20 GR < 2.5 and 15 AES < 55)
Equation CSTW=0.229+2.65×106×AES30.0403×ln(AES)+0.0214×GR2+0.00392×AES×GR
3 Condition (1.5 < GR 0 and AES < 15)
or (AES/10 < GR < AES/20 and 15 AES < 55)
Equation CSTW=0.08+3.0×106×AES3+0.029×GR2+0.0828×GR+0.000056×AES2×GR
4 Condition (GR 1.5 and AES < 15)
or (GR AES/10 and 15 AES < 55)
Equation CSTW=exp(5.220.000771×AES2+0.0843×GR+2.81×ln(GR)0.00323×AES×GR)
5 Condition GR 0.5 and AES 55
Equation CSTW=1.318+0.000743×AES20.05661×AES+0.01941×GR2+0.00417×AES×GR
6 Condition (AES/10+1 < GR < 0.5 and AES 55)
or (GR < 0.5 and AES 80)
Equation CSTW=0.2022+0.000237×AES2+0.0213×GR21.0322×GR+0.3099×ln(AES)×GR
7 Condition otherwise
Equation CSTW=0.2613+0.000164×AES2+0.02065×GR2+0.005452×AES×GR0.03975×ln(AES)×GR
E.4.4 Constant-Speed Maintenance and Repair (CSMR)
Table E-18. Medium/Large Automobile Constant-Speed Maintenance and Repair
1 Condition GR0
Equation CSMR=48.4+0.00867×AES2+0.0577×AES×GR
2 Condition (1.5 GR < 0 and AES 25)
or (GR < 0 and 12.2×GR+4 AES and 25 < AES < 55)
Equation CSMR=45.19+0.00584×AES2+0.229×AES+0.0562×AES×GR
3 Condition (GR < 1.5 and AES 25)
or (GR < 0 and 12.2×GR+4 > AES and 25 < AES < 55)
Equation CSMR=6.670.018×AES223.4×GR
4 Condition 0.14×AES+3.6 < GR < 0 and AES 55
Equation CSMR=72.46+0.01373×AES20.7081×AES+0.05597×AES×GR
5 Condition otherwise
Equation CSMR=5.4150.01912×AES223.51×GR
E.4.5 Constant-Speed Depreciation (CSVD)
Table E-19. Medium/Large Automobile Constant-Speed Vehicle Depreciation
1 Condition all
Equation CSVD=1.725+0.001892×AES0.311×ln(AES)
E.4.6 Excess Fuel Consumption Due to Speed Variability (SCCFC)
Table E-20. Medium/Large Automobile Excess Fuel Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCFC=0.008×CSMAX3
2 Condition CSMAX 5
Equation SCCFC=0.03401+0.1902×CSMAX+4491×108×CSMAX3
E.4.7 Excess Oil Consumption Due to Speed Variability (SCCOC)
Table E-21. Medium/Large Automobile Excess Oil Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCOC=0.00004×CSMAX3
2 Condition CSMAX 5
Equation SCCOC=0.000801+0.000869×CSMAX1617×108×CSMAX2+197×108×CSMAX3
E.4.8 Excess Tire Wear Due to Speed Variability (SCCTW)
Table E-22. Medium/Large Automobile Excess Tire Wear Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCTW=0.0012×CSMAX2
2 Condition CSMAX 5
Equation SCCTW=exp(6.64+1.947×ln(CSMAX)9909×108×CSMAX2)
E.4.9 Excess Maintenance and Repair Due to Speed Variability (SCCMR)
Table E-23. Medium/Large Automobile Excess Maintenance and Repair Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCMR=0.0016×CSMAX2
2 Condition CSMAX 5
Equation SCCMR=exp(6.277+0.007347×CSMAX+1.876×ln(CSMAX)7275×108×CSMAX2)
E.4.10 Excess Depreciation Due to Speed Variability (SCCD)
Table E-24. Medium/Large Automobile Depreciation Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCD=0.0004×CSMAX
2 Condition 5 CSMAX < 50
Equation SCCD=0.001+0.0002×CSMAX
3 Condition CSMAX 50
Equation SCCD=exp(4.973+0.000228×CSMAX2)
E.4.11 Excess Fuel Consumption Due to Curves (CFC)
Table E-25. Medium/Large Automobile Excess Fuel Consumption Due to Curves
1 Condition DCA 5 and AES 1/(0.0137 + 0.0123×DCA0.5 + 0.0299/DCA0.5)
Equation CFC = MAX(0, 0.34211 + 0.28291×DCA + 0.014828×AES 0.016971×DCA2 0.00024465×AES2 0.0047869×DCA×AES)
2 Condition DCA > 5 and AES 1/(0.0137 + 0.0123×DCA0.5 + 0.0299/DCA0.5)
Equation CFC = MAX(0, 0.79434 + 1.1403×LN(DCA) + 0.052408×AES 0.1933×(LN(DCA))2 0.00060403×AES2 0.028889×AES×LN(DCA))
3 Condition AES > 1/(0.0137 + 0.0123×DCA0.5 + 0.0299/DCA0.5)
Equation CFC = MAX(0, EXP(18.864 0.02183×DCA(1.5) + 2.6113×DCA(0.5) + 1.80792×AES(0.5)))
E.4.12 Excess Tire Wear Due to Curves (CTW)
Table E-26. Medium/Large Automobile Excess Tire Wear Due to Curves
1 Condition (DCA 16 and AES (0.031746×DCA2 +0.74603×DCA +21.19))
or (6 DCA < 16 and AES (45 1.9167×DCA + 0.041667×DCA2))
or (DCA < 6 and AES (442.3 + 2959.4/DCA(0.5) 6735.1/DCA + 6810.6/DCA(1.5) 2582.5/DCA2))
Equation CTW = MAX(0, 519464×EXP( EXP( (DCA 48.665)/18.647) (DCA 48.665)/18.647 + 1) × EXP( EXP( (AES 127.84)/39.862) (AES 127.84)/39.862 + 1))
2 Condition (DCA 16 and AES < (0.031746×DCA2 +0.74603×DCA +21.19))
or (6 DCA < 16 and AES < (45 1.9167×DCA + 0.041667×DCA2))
Equation CTW = MAX(0, 31.7 + 20.767×LN(DCA) + 22.783×LN(AES) 2.5841×(LN(DCA))2 3.9522×(LN(AES))2 4.4831×LN(DCA)×LN(AES))
3 Condition DCA < 6 and AES < (442.3 + 2959.4/DCA(0.5) 6735.1/DCA + 6810.6/DCA(1.5) 2582.5/DCA2)
Equation CTW = MAX(0, 4.4955 + 4.542×DCA + 0.088792×AES 0.27253×DCA2 0.00042329×AES2 0.07399×DCA×AES)
E.4.13 Excess Maintenance and Repair Due to Curves
Table E-27. Medium/Large Automobile Excess Maintenance and Repair Due to Curves
1 Condition (DCA > 12 and AES (0.5×DCA + 30))
or (DCA < 12 and AES (2.3636×DCA + 52.364))
Equation CMR = MAX(0, EXP(37.927 + 3.2935×LN(DCA) + 1.8096/DCA + 7.8477×LN(AES)))
2 Condition 5 DCA 10 and (1×DCA + 20) AES (1×DCA 25)
Equation CMR = 0.1
3 Condition Otherwise
Equation CMR = 0

E.5 4-Tire Trucks

E.5.1 Constant-Speed Fuel Consumption (CSFC)
Table E-28. 4-Tire Truck Constant-Speed Fuel Consumption
1 Condition GR 0 and 20 < AES < 55
Equation CSFC = 115.41 3.6397×AES + 7.0832×GR + 0.050662×AES2 0.34401×GR2 + 0.096956×AES×GR
2 Condition GR 0 and AES 20
Equation CSFC = 120.7 + 5.0201×AES + 0.1088×AES2 + 9.8816×GR 1.3755×GR2 + 0.11582×GR3
3 Condition GR < 0 and AES 10
Equation CSFC = 161.2 6.622×AES 87.758×ln(AES)/AES 1.0889×GR2 0.13217×GR3
4 Condition GR < 0 and 10 < AES 20
Equation CSFC = 106.31 2.7456×AES + 5.0147×GR 0.001281×AES2 + 0.94555×GR2 + 0.19499×AES×GR
5 Condition GR < 0 and 20 < AES < 55
Equation CSFC = 351.5 184.42×ln(AES) + 0.71838×GR + 28.297×(ln(AES))2 + 1.0105×GR2 + 2.8947×GR×ln(AES)
6 Condition GR 1.5 and AES 55
Equation CSFC = 110.4 + 0.000249×AES3 18.93×ln(AES) + 8.06×GR
7 Condition 2.5 GR < 1.5 and AES 55
Equation CSFC = (28.77 + 0.183655×AES + 3.34032×GR) / (1 0.0074966×AES 0.049703×GR)
8 Condition Otherwise
Equation CSFC = exp(2.784 + 0.02014×AES + 0.06881×GR)
E.5.2 Constant-Speed Oil Consumption (CSOC)
Table E-29. 4-Tire Truck Constant-Speed Oil Consumption
1 Condition Condition GR > 0 and AES < 50
Equation CSOC=exp(2.470.604×ln(AES)0.00994×GR2+0.277×GR0.001248×AES×GR)
2 Condition GR > 0 and 50 AES 70
Equation CSOC=16.41+0.004424×AES20.5255×AES+1.296×GR0.2664×ln(AES)×GR
3 Condition GR > 0 and AES > 70
Equation CSOC=16.41+0.004424×AES20.5255×AES+0.19×GR
4 Condition min(3.5, AES/6.0) < GR 0 and AES < 50
Equation CSOC=8.45+0.0000352×AES30.00567×AES2+0.370×AES4.12×ln(AES)
5 Condition GR < min(3.5, AES/6.0) and AES < 50
Equation CSOC=exp(0.920.000295×AES20.751×ln(AES) 0.0269×GR20.584×GR)
6 Condition otherwise
Equation CSOC=16.41+0.004424×AES20.5255×AES
E.5.3 Constant-Speed Tire Wear
Table E-30. 4-Tire Truck Constant-Speed Tire Wear
1 Condition GR 2.5 and AES < 55
Equation CSTW = EXP(2.08 + 0.0001517×AES2 + 0.012×AES + 1.367×LN(GR) 0.001389×AES×GR)
2 Condition (0 < GR < 2.5 and AES < 15)
or (AES/20 < GR < 2.5 and 15 AES < 55)
Equation CSTW = 0.297 + 2.9×10(6)×AES3 0.0421×LN(AES) + 0.0234×GR2 + 0.00429×AES×GR
3 Condition (2.5 < GR 0 and AES < 15)
or (AES/10 < GR AES/20 and 15 AES < 55)
Equation CSTW = 0.1294 + 3.64×10(6)×AES3 + 0.0324×GR2 + 0.1085×GR + 0.0000631×AES2×GR
4 Condition (GR 2.5 and AES < 15)
or (GR < AES/10 and 15 AES < 55)
Equation CSTW = EXP(5.45 4.13×10(6)×AES3 0.01377×AES + 2.79×LN(GR))
5 Condition GR 0.5 and AES 55
Equation CSTW = 1.365 + 0.000736×AES2 0.05471×AES + 0.0197×GR2 + 0.004395×AES×GR
6 Condition ((AES/10+1) < GR < 0.5 and AES 55)
or (GR < 0.5 and AES 80)
Equation CSTW = ABS(0.1554 + 0.000258×AES2 + 0.0205×GR2 0.05138×GR + 0.005058×AES×GR)
7 Condition Otherwise
Equation CSTW = MAX(0.01, 0.2177 + 0.000208×AES2 + 0.02376×GR2 + 0.005895×AES×GR 0.03288×LN(AES)×GR)
E.5.4 Constant-Speed Maintenance and Repair
Table E-31. 4-Tire Truck Constant-Speed Maintenance and Repair
1 Condition GR 0
Equation CSMR=49.2+0.00881×AES2+0.0545×AES×GR
2 Condition (1.5 GR < 0 and AES 20)
or (GR < 0 and 20 < AES < 55 and AES10×GR+6)
Equation CSMR=46.0+0.00595×AES2+0.231×AES+0.0531×AES×GR
3 Condition (GR < 1.5 and AES 20)
or (GR < 0 and 20 < AES < 55 and AES < 10×GR+6)
Equation CSMR=12.430.019×AES223.5×GR
4 Condition (GR <0 and AES 55 and GR > 0.1×AES+0.75)
or (GR < 0 and AES>70)
Equation CSMR=72.36+0.01373×AES20.6841×AES+0.0532×AES×GR
5 Condition otherwise
Equation CSMR=13.830.0197×AES224.01×GR
E.5.5 Constant-Speed Depreciation (CSVD)
Table E-32. 4-Tire Truck Constant-Speed Vehicle Depreciation
1 Condition all
Equation CSVD = 0.742+0.000589×AES0.1307×ln(AES)
E.5.6 Excess Fuel Consumption Due to Speed Variability (SCCFC)
Table E-33. 4-Tire Truck Excess Fuel Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCFC=0.00904×CSMAX3
2 Condition CSMAX 5
Equation SCCFC=0.8137+0.1576×CSMAX+7327×108×CSMAX3
E.5.7 Excess Oil Consumption Due to Speed Variability (SCCOC)
Table E-34. 4-Tire Truck Excess Oil Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCOC=0.0002×CSMAX2
2 Condition CSMAX 5
Equation SCCOC=exp(6.242+0.5935×ln(CSMAX)+0.000131×CSMAX2)
E.5.8 Excess Tire Wear Due to Speed Variability (SCCTW)
Table E-35. 4-Tire Truck Excess Tire Wear Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCTW=0.0012×CSMAX2
2 Condition CSMAX 5
Equation SCCTW=exp(6.568+1.906×ln(CSMAX)7502×108×CSMAX2)
E.5.9 Excess Maintenance and Repair Due to Speed Variability (SCCMR)
Table E-36. 4-Tire Truck Excess Maintenance and Repair Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCMR=0.0016×CSMAX2
2 Condition CSMAX 5
Equation SCCMR=exp(6.39+1.958×ln(CSMAX)1781×108×CSMAX2)
E.5.10 Excess Depreciation Due to Speed Variability (SCCD)
Table E-37. 4-Tire Truck Excess Depreciation Due to Speed Variability
1 Condition CSMAX < 60
Equation SCCD=0.0002×CSMAX
2 Condition CSMAX 60
Equation SCCD=exp(5.0007+0.000162×CSMAX2)
E.5.11 Excess Fuel Consumption Due to Curves (CFC)
Table E-38. 4-Tire Truck Excess Fuel Consumption Due to Curves
1 Condition (DCA < 6 and AES (0.5682×DCA2 + 0.75×DCA + 55.818))
or (DCA 6 and AES (0.0055×DCA2 0.7634×DCA + 43.597))
Equation CFC = MAX(0, EXP(779.63 1.2743×DCA + 3.1889×DCA(0.5)×LN(DCA) 2.9306×DCA(0.5) 25.106×AES(0.5) 10108.5/AES(0.5) + 10588.5×LN(AES)/AES))
2 Condition (DCA 10 and AES (57.993 + 1.1162×DCA 13.963×DCA0.5))
or (8 DCA < 10 and AES 25)
Equation CFC = MAX(0, 0.45381 + 0.98231×LN(DCA) + 0.10049×AES 0.15×(LN(DCA))2 0.0011603×AES2 0.046122×AES×LN(DCA))
3 Condition 4 DCA < 8 and AES (2.5×DCA + 45)
Equation CFC = MAX(0, 2.0296 + 2.4402×LN(DCA) + 0.087398×AES 0.50234×(LN(DCA))2 0.0012841×AES2 0.036879×AES×LN(DCA))
4 Condition (2 DCA < 4 and AES 35)
or (DCA < 2 and AES (2.5×DCA + 30))
Equation CFC = MAX(0, EXP(0.0010091 5.4673/DCA2 0.082805×AES + 0.011991×AES2 0.0018375×AES(2.5)))
5 Condition Otherwise
Equation CFC = 0
E.5.12 Excess Tire Wear Due to Curves (CTW)
Table E-39. 4-Tire Truck Excess Tire Wear Due to Curves
1 Condition (DCA 16 and AES (0.02381×DCA2 1.4524×DCA + 42.143))
or (6 DCA < 16 and AES (35 125/DCA + 750/DCA2))
or (DCA < 6 and AES (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3))
Equation CTW = MAX(0, 450515×EXP( EXP( (DCA 49.07)/18.816) (DCA 49.07)/18.816 + 1) × EXP( EXP( (AES 124.84)/38.88) (AES 124.84)/38.89 + 1))
2 Condition DCA 16 and AES < (0.02381×DCA2 1.4524×DCA + 42.143)
Equation CTW = MAX(0, 13.126 + 79.095/DCA + 254.26/AES 39.567/DCA2 694.97/AES2 217.62/(DCA×AES))
3 Condition (6 DCA < 16 and AES < (35 125/DCA + 750/DCA2))
or (DCA < 6 and AES < (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3)
Equation CTW = MAX(0, 2.743 + 3.5215×DCA + 0.077273×AES 0.16376×DCA2 0.00069592×AES2 0.064592×DCA×AES)
E.5.13 Excess Maintenance and Repair Due to Curves
Table E-40. 4-Tire Truck Excess Maintenance and Repair Due to Curves
1 Condition (DCA 12 and AES (0.45×DCA + 30.4))
or (DCA < 12 and AES (2.2727×DCA + 52.273))
Equation CMR = MAX(0, EXP(594.56 0.021279×DCA(1.5) + 2.6656×DCA(0.5) 19.444×AES(0.5) 7777/AES(0.5) + 8121.8×LN(AES)/AES))
2 Condition (3.5 < DCA < 8.5 and 17.5 AES < 22.5)
or (4.5 < DCA < 10.5 and 12.5 AES 17.5)
or (7.5 < DCA < 12.5 and 7.5 < AES <= 12.5)
Equation CMR = 0.1
3 Condition Otherwise
Equation CMR = 0

E.6 6-Tire Truck

E.6.1 Constant-Speed Fuel Consumption (CSFC)
Table E-41. 6-Tire Truck Constant-Speed Fuel Consumption
1 Condition GR 0 and AES < 55
Equation CSFC = 298.60 13.131×AES + 53.987×GR + 0.30096×AES2 4.7321×GR2 0.88407×AES×GR 0.0020906×AES3 + 0.22739×GR3 + 0.02875×AES×GR2 + 0.0045428×AES2×GR
2 Condition GR < 0 and AES < 55
Equation CSFC = 273.05 9.2427×AES +58.195×GR + 0.14718×AES2 + 6.7665×GR2 1.3785×AES×GR 0.00046068×AES3 + 0.13884×GR3 0.079555×AES×GR2 + 0.012622×AES2×GR
3 Condition GR 1.5 and AES 55
Equation CSFC = 361.11 8.1978×AES + 11.186×GR + 0.077607×AES20.27665×GR2 0.035211×AES×GR
4 Condition GR < 1.5 and AES 55
Equation CSFC = 101.5 + 0.000186×AES3 + 1.102×GR2 + 18.22×GR
E.6.2 Constant-Speed Oil Consumption (CSOC)
Table E-42. 6-Tire Truck Constant-Speed Oil Consumption
1 Condition GR > 0 and AES < 55
Equation CSOC = exp(3.8424 0.93964×ln(AES) 1.7418/AES + 0.80327×GR(0.5))
2 Condition GR > 0 and AES 55
Equation CSOC = 51.76 + 0.002513×AES2 14.29×ln(AES)+ 0.7485×GR
3 Condition (1.5 < GR 0 and AES < 55)
or (AES/10 GR 0 and AES < 55)
Equation CSOC = 13.98 + 0.0000603×AES3 0.00857×AES2 + 0.523×AES 6.17×ln(AES)
4 Condition GR < AES/10 and AES 70
Equation CSOC = exp(1.41 + 0.000519×AES2 0.0845×AES 0.0344×GR2 0.649×GR)
5 Condition Otherwise
Equation CSOC = 51.76 + 0.002513×AES2 14.29×ln(AES)
E.6.3 Constant-Speed Tire Wear (CSTW)
Table E-43. 6-Tire Truck Constant-Speed Tire Wear
1 Condition GR 2.5 and AES<55
Equation CSTW=exp(1.572+0.0000943×AES2+0.01509×AES+1.65×ln(GR)0.001535×AES×GR)
2 Condition GR 2.5 and AES 55
Equation CSTW=2.206+0.001267×AES20.09683×AES+0.07733×GR2+0.01096×AES×GR
3 Condition (0 < GR < 2.5 and AES<15)
or (AES/25 < GR <2.5 and AES15)
Equation CSTW=0.353+4.5×106×AES30.0556×ln(AES)+0.0855×GR2+0.01012×AES×GR
4 Condition (1.5 < GR 0 and AES < 15)
or (AES/14 < GR < AES/25 and AES 15)
Equation CSTW=0.104+5.37×108×AES4+0.0001578×AES2+0.1282×GR2+0.222×GR+0.000168×AES2×GR
5 Condition otherwise
Equation CSTW=exp(3.163.35×106×AES30.0308×AES+2.28×ln(GR)0.00377×AES×GR)
E.6.4 Constant-Speed Maintenance and Repair (CSMR)
Table E-44. 6-Tire Truck Constant-Speed Maintenance and Repair
1 Condition 4 GR 1 and AES > (1.6667×GR3 17.5×GR2 70.833×GR 45) and AES < (1.6667 ×GR3 17.5×GR2 70.833×GR 40)
Equation CSMR = 1/(0.96223 + 2.3017e06×AES3 0.33129×exp(AES/44.4878) + 0.48203/GR 0.00029083×exp(GR))
2 Condition (GR 1)
or (GR < 1 and AES (1.6667 ×GR3 17.5×GR2 70.833×GR 40))
Equation CSMR = 44.2 + 0.01147×AES2 + 0.1462×AES×GR
3 Condition Otherwise
Equation CSMR = 0.722 0.00697×AES2 15.9×GR
E.6.5 Constant-Speed Depreciation (CSVD)
Table E-45. 6-Tire Truck Constant Speed Vehicle Depreciation
1 Condition AES < 55
Equation CSVD=1.126+0.0028×AES0.247×ln(AES)
2 Condition AES 55
Equation CSVD=0.2006+4.936/AES
E.6.6 Excess Fuel Consumption Due to Speed Variability (SCCFC)
Table E-46. 6-Tire Truck Excess Fuel Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCFC=0.1184×CSMAX2
2 Condition CSMAX 5
Equation SCCFC=3.09+0.02843×CSMAX2
E.6.7 Excess Oil Consumption Due to Speed Variability (SCCOC)
Table E-47. 6-Tire Truck Excess Oil Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCOC=0.00068×CSMAX2
2 Condition CSMAX 5
Equation SCCOC=exp(5.069+0.6392×ln(CSMAX)+0.000169×CSMAX2)
E.6.8 Excess Tire Wear Due to Speed Variability (SCCTW)
Table E-48. 6-Tire Truck Excess Tire Wear Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCTW=0.0016×CSMAX2
2 Condition CSMAX 5
Equation SCCTW=exp(6.387+1.984×ln(CSMAX)988×107×CSMAX2)
E.6.9 Excess Maintenance and Repair Due to Speed Variability (SCCMR)
Table E-49. 6-Tire Truck Excess Maintenance and Repair Due to Speed Variability
1 Condition CSMAX 5
Equation SCCMR=0.0012×CSMAX2
2 Condition CSMAX>5
Equation SCCMR=exp(6.427+0.01826×CSMAX+1.758×ln(CSMAX)0.000103×CSMAX2)
E.6.10 Excess Depreciation Due to Speed Variability (SCCD)
Table E-50. 6-Tire Truck Excess Depreciation Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCD=0.0004×CSMAX
2 Condition 5 CSMAX < 40
Equation SCCD=0.001429+0.000221×CSMAX
3 Condition CSMAX 40
Equation SCCD=exp(4.957+0.000294×CSMAX2)
E.6.11 Excess Fuel Consumption Due to Curves (CFC)
Table E-51. 6-Tire Truck Excess Fuel Consumption Due to Curves
1 Condition (DCA 10 and AES (27.9 0.0144×DCA2 + 300/DCA2))
or (2 DCA < 10 and AES (1/(0.0127 + 0.00484×DCA 0.000675×DCA2 + 3.97e05 × DCA3)))
or (DCA < 2 and AES (1/(0.0286 + 0.00429×DCA 0.00429×DCA2)))
Equation CFC = MAX(0, EXP(50.349 0.98363×DCA 0.05974×DCA2 + 59.476×EXP(DCA/ 31.649) 90.158/AES(0.5)))
2 Condition DCA 5 and AES (27.9 0.0144 × DCA2 + 300/DCA2)
Equation CFC = MAX(0, 9.7649 + 7.88×LN(DCA) + 6.036×LN(AES) 1.0423×(LN(DCA))2 1.053×(LN(AES))2 1.464×LN(DCA)×LN(AES))
3 Condition 1 < DCA < 5 and AES (30 + 70/DCA 100/DCA2)
Equation CFC = MAX(0, EXP(1.604 4.6423/DCA(1.5) 0.000062414×AES3))
4 Condition Otherwise
Equation CFC = 0
E.6.12 Excess Tire Wear Due to Curves (CTW)
Table E-52. 6-Tire Truck Excess Tire Wear Due to Curves
1 Condition (DCA 16 and AES (0.02381×DCA2 1.4524×DCA + 42.143))
or (6 DCA < 16 and AES (35 125/DCA + 750/DCA2))
or (DCA < 6 and AES (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3))
Equation CTW = MAX(0, 377675×EXP( EXP( (DCA 51.703)/19.791) ( DCA 51.703)/19.791 + 1) × EXP( EXP( (AES 120.93)/37.611) (AES 120.93)/37.611 + 1))
2 Condition (DCA 16 and AES < (0.02381×DCA2 1.4524×DCA + 42.143))
or (6 DCA < 16 and AES < (35 125/DCA + 750/DCA2))
Equation CTW = MAX(0, 26.586 + 17.42×LN(DCA) + 19.303×LN(AES) 2.1482×(LN(DCA))2 3.3487×(LN(AES))2 3.81×LN(DCA)×LN(AES))
3 Condition DCA < 6 and AES < (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3)
Equation CTW = MAX(0, 4.0066 + 3.8372×DCA + 0.11043×AES 0.2262×DCA2 0.0011358×AES2 0.064529×DCA×AES)
E.6.13 Excess Maintenance and Repair Due to Curves

The fourth equation for 6-Tire Truck excess maintenance and repair due to curves is incremental - the condition is true when certain other conditions are true and the equation adds value to the existing CMR value.

Table E-53. 6-Tire Truck Excess Maintenance and Repair Due to Curves
1 Condition DCA 8 and AES (0.0038×DCA2 0.3106×DCA + 27.272)
Equation CMR = MAX(0, EXP(9.6157 + 0.12975×DCA 157.95/DCA2 + 7095.5×EXP(DCA) 106.49×LN(AES)/AES))
2 Condition DCA < 8 and AES (0.625×DCA2 + 3.125×DCA + 40)
Equation CMR = MAX(0, EXP(314.6 + 2.5973×DCA×LN(DCA) 1.4569×DCA2 + 0.30227×DCA(2.5) + 2642/LN(AES) 2565.9/AES(0.5)))
3 Condition (1 DCA 3 and (10×DCA + 37.5) < AES < (10×DCA + 2.5))
or (3 < DCA 5 and AES < 32.5)
or (5 < DCA < 8 and AES < (0.8333×DCA2 14.167×DCA +85))
or (DCA 8 and AES < (0.0038×DCA2 0.3106×DCA + 24.5))
Equation CMR = 0.1
4 Condition DCA > 4.5 and 12.5 < AES < (0.35×DCA2 + 3.85×DCA + 12)
Equation CMR = CMR + 0.1
5 Condition Otherwise
Equation CMR = 0

E.7 3+ Axle Single-Unit Truck

E.7.1 Constant-Speed Fuel Consumption (CSFC)
Table E-54. 3+ Axle Single-Unit Truck Constant-Speed Fuel Consumption
1 Condition Condition GR 3 and AES 20
Equation CSFC = 68.536 + 12.823×AES + 122.45×GR + 0.023896×AES2 + 0.36758×GR2 6.2014×AES×GR
2 Condition 3 GR 0 and AES 20
Equation CSFC = 254 3.0854×AES 2.177×GR 0.063346×AES2 + 24.848×GR2 + 4.3101×AES×GR + 0.0012816×AES3 1.2432×GR3 1.6437×AES×GR2 + 0.0013556×AES2×GR
3 Condition GR < 0 and AES 20
Equation CSFC = (259.66 19.925×AES+ 0.49931×AES2 0.0045651×AES3 1.5876×GR)/(1 0.058535×AES + 0.00077356×AES2 0.14916×GR + 0.024241×GR2)
4 Condition GR > 3 and AES > 20
Equation CSFC = 290.45 2.598×AES + 25.823×GR + 0.024983×AES2 2.2654×GR2 + 0.21897×AES×GR
5 Condition 3 GR 0 and AES > 20
Equation CSFC = 1208.8 586.87×LN(AES) + 80.955×(ln(AES))2+ 93.99×GR 13.477×GR2
6 Condition 0 > GR 3 and AES > 20
Equation CSFC = exp(6.0673 0.1139×AES + 0.023622×AES×ln(AES) + 0.79191×GR 0.022171×GR3)
7 Condition GR < 3 and AES > 20
Equation CSFC = (1.3978/(1 + (((AES 40.215)/11.403)2))) + (47.024/(1 + (((GR + 0.01611)/5.4338)2))) + (26.724/(1 + (((AES 40.215)/11.403)2))) × (1/(1 + (((GR + 0.01611)/5.4338)2)))
E.7.2 Constant-Speed Oil Consumption (CSOC)
Table E-55. 3+ Axle Single-Unit Truck Constant-Speed Oil Consumption
1 Condition Condition GR > 0 and AES<55
Equation CSOC=exp(4.36+0.00711×AES0.869×ln(AES)0.01712×GR2+0.338×GR)
2 Condition min(1.5,AES/12.5) < GR 0 and AES<55
Equation CSOC=20.2+0.0000724×AES30.0103×AES2+0.662×AES8.52×ln(AES)
3 Condition GR min(1.5,AES/12.5) and AES < 55
Equation CSOC=exp(1.77+0.00055×AES20.0769×AES0.0343×GR20.646×GR)
4 Condition GR > 0 and AES 55
Equation CSOC=22.85+0.006514×AES20.7188×AES+1.615×GR
5 Condition (AES/12.5 GR 0 and AES 55) or (GR 0 and AES 90)
Equation CSOC=22.85+0.006514×AES20.7188×AES
6 Condition otherwise
Equation CSOC=exp(1.77+0.00055×AES20.0769×AES0.0343×GR20.646×GR)
E.7.3 Constant-Speed Tire Wear (CSTW)
Table E-56. 3+ Axle Single-Unit Truck Constant-Speed Tire Wear
1 Condition Condition GR 2.5 and AES<55
Equation CSTW=exp(1.71+0.0000511×AES2+0.01134×AES+1.575×ln(GR)0.001038×AES×GR)
2 Condition GR 2.5 and AES 55
Equation CSTW=1.085+0.000405×AES20.03274×AES+0.05955×GR2+0.00577×AES×GR
3 Condition (0.5 < GR < 2.5 and AES<15) or (AES/30 < GR <2.5 and AES15)
Equation CSTW=0.0896+0.0001308×AES2+0.0552×GR2+0.1181×GR+0.00402×AES×GR
4 Condition AES/20 < GR AES/30 and AES15
Equation CSTW=0.0345+0.000387×AES2+0.257×GR2+0.01988×AES×GR
5 Condition otherwise
Equation CSTW=exp(3.300.0275×AES+0.1868×GR+2.92×ln(GR)0.00275×AES×GR)
E.7.4 Constant-Speed Maintenance and Repair (CSMR)
Table E-57. 3+ Axle Single-Unit Truck Constant-Speed Maintenance and Repair
1 Condition 4 GR 1 and AES > (1.6667×GR3 17.5×GR2 75.833×GR 45) and AES < ( 1.6667 ×GR3 17.5×GR2 75.833×GR 40)
Equation CSMR = 1046.8 499.21×ln(AES) + 106.76×(ln(AES))2 + 601.98×GR + 154.36×GR2 + 15.039×GR3
2 Condition (GR 1) or (GR < 1 and AES (1.6667 ×GR3 17.5×GR2 75.833×GR 40))
Equation CSMR = 46 + 0.008×AES2 + 0.146×AES×GR
3 Condition Otherwise
Equation CSMR = 1.6996 + 0.094776×AES 0.016324×AES2 + 0.00037673×AES3 4.0767e06×AES4 + 1.4984e08×AES5 14.684×GR
E.7.5 Constant-Speed Depreciation (CSVD)
Table E-58. 3+ Axle Single-Unit Constant-Speed Vehicle Depreciation
1 Condition AES < 55
Equation CSVD=1.126+0.00279×AES0.247×ln(AES)
2 Condition otherwise
Equation CSVD=0.2006+4.936/AES
E.7.6 Excess Fuel Consumption Due to Speed Variability (SCCFC)
Table E-59. 3+ Axle Single-Unit Truck Excess Fuel Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCFC=0.174×CSMAX2
2 Condition CSMAX 5
Equation SCCFC=4.477+0.03862×CSMAX2
E.7.7 Excess Oil Consumption Due to Speed Variability (SCCOC)
Table E-60. 3+ Axle Single-Unit Truck Excess Oil Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCOC=0.00136×CSMAX2
2 Condition CSMAX 5
Equation SCCOC=exp(4.408+0.6632×ln(CSMAX)+0.000148×CSMAX2)
E.7.8 Excess Tire Wear Due to Speed Variability (SCCTW)
Table E-61. 3+ Axle Single-Unit Truck Excess Tire Wear Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCTW=0.0012×CSMAX2
2 Condition CSMAX 5
Equation SCCTW=exp(6.595+1.918×ln(CSMAX)6855×108×CSMAX2)
E.7.9 Excess Maintenance and Repair Due to Speed Variability (SCCMR)
Table E-62. 3+ Axle Single-Unit Truck Excess Maintenance and Repair Due to Speed Variability
1 Condition Condition CSMAX < 5
Equation SCCMR=0.0008×CSMAX2
2 Condition CSMAX 5
Equation SCCMR=exp(7.4460.005514×CSMAX+2.212×ln(CSMAX)+ 5075×108×CSMAX2)
E.7.10 Excess Depreciation Due to Speed Variability (SCCD)
Table E63. 3+ Axle Single-Unit Truck Depreciation Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCD=0.0006×CSMAX
2 Condition 5 CSMAX < 55
Equation SCCD=0.001+0.0004×CSMAX
3 Condition CSMAX 55
Equation SCCD=exp(4.439+0.000231×CSMAX2)
E.7.11 Excess Fuel Consumption Due to Curves (CFC)
Table E-64. 3+ Axle Single-Unit Truck Excess Fuel Consumption Due to Curves
1 Condition (DCA 6 and AES (44.375 1.8236×DCA + 0.02044×DCA2 + 0.0018571×DCA2 0.000053954×DCA2))
or (6 > DCA 2 and AES (39.5 + 4.1667×DCA 0.83333×DCA2))
Equation CFC = EXP(371.346 + 5.1878×LN(DCA) + 10.1521/DCA(0.5) 12.1424×AES(0.5) 4915.79/AES(0.5) + 5093.19×LN(AES)/AES))
2 Condition DCA < 2 and AES (24.5 10×DCA + 10×DCA2)
Equation CFC = MAX(0, 1.3873+ 38.977×EXP( 0.5×(((DCA2.2124)/1.071)2 + ((AES102.44)/16.633)2)))
3 Condition 2 DCA 16 and AES < 10
Equation CFC = MAX(0, 4.0824 + 1.833×DCA 0.15946×DCA2 + 0.0044245×DCA3 + 0.56919×AES 0.038513×AES2 + 0.00079158×AES3)
4 Condition DCA 1 and AES < 25
Equation CFC = 0
5 Condition Otherwise
Equation CFC = MAX(0, 8.9743 0.099969×DCA +16.366×LN(AES)+ 0.0052265×DCA2 3.6805×(LN(AES))2 0.11371×DCA×LN(AES))
E.7.12 Excess Tire Wear Due to Curves (CTW)
Table E-65. 3+ Axle Single Unit Truck Excess Tire Wear Due to Curves
1 Condition (DCA 16 and AES (0.02381×DCA2 1.4524×DCA + 42.143))
or (16 > DCA 6 and AES (35 125/DCA + 750/DCA2))
or (DCA < 6 and AES (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA2))
Equation CTW = MAX(0, 707192×EXP( EXP( (DCA 44.524)/16.77) (DCA 44.524)/16.77 + 1) × EXP( EXP( (AES 132.23)/40.729) (AES 132.23)/40.729 + 1))
2 Condition (DCA 16 and AES < (0.02381×DCA2 1.4524×DCA + 42.143))
or (16 > DCA 6 and AES < (35 125/DCA + 750/DCA2))
Equation CTW = MAX(0, 7.4369 + 29.473/DCA + 6.5816×LN(AES) 541.46/DCA2 3.8133×(LN(AES))2 + 45.797×(LN(AES))/DCA)
3 Condition DCA < 6 and AES < (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3)
Equation CTW = MAX(0, 4.6194 + 4.5401×DCA + 0.10837×AES 0.26588×DCA2 0.00099725×AES2 0.076619×DCA×AES)
E.7.13 Excess Maintenance and Repair Due to Curves

The third equation for 3+ Axle Single Unit Truck excess maintenance and repair due to curves is used to increment the value for CMR derived from the second equation under certain conditions. These conditions for this may be true when the condition for equation two is true.

Table E-66. 3+ Axle Single Unit Truck Excess Maintenance and Repair Due to Curves
1 Condition (DCA 10 and AES (0.75×DCA + 40))
or (10 > DCA 2 and AES (2.1875×DCA + 54.375))
or (DCA < 2 and AES (5×DCA22.5×DCA+35))
Equation CMR = MAX(0, EXP(50.038+ 0.71092×(LN(DCA))2 + 0.50522×LN(DCA) 0.08522×AES + 13.02×LN(AES)))
2 Condition (1 DCA 3 and (10×DCA + 2.5) AES (10×DCA + 37.5))
or (3 < DCA 5 and AES 32.5)
or (DCA 14 and AES (0.3125×DCA + 21.875))
or (5 < DCA < 14 and AES (1.66667×DCA + 40.8333))
Equation CMR = 0.1
3 Condition 4.5 DCA 10.5 and AES > (39.3 13.497×DCA + 2.215×DCA2 0.11833×DCA3) and AES < (17.5 + 5/(1 + exp( ((DCA 7.0222)/0.07845))))
Equation CMR = CMR + 0.1
4 Condition Otherwise
Equation CMR = 0

E.8 3-4 Axle Combination Unit Truck

E.8.1 Constant-Speed Fuel Consumption (CSFC)
Table E-67. 3-4 Axle Combination Unit Truck Constant-Speed Fuel Consumption
1 Condition (AES > 20 and 3 GR 3) or (AES 20 and GR 3)
Equation CSFC = (1087.9 576.71×LN(AES) 82.039×(LN(AES))2 + 22.325×GR)/(1 0.17121×LN(AES) 0.035147×GR)
2 Condition GR < 3
Equation CSFC = 239.17 + 61.115×LN(AES) + 2221.9/AES 4411.6×EXP(AES)
3 Condition AES > 20 and GR > 3
Equation CSFC = EXP(4.5952 + 0.0049349×AES×LN(AES) + 0.31272×GR)
E.8.2 Constant-Speed Oil Consumption (CSOC)
Table E-68. 3-4 Axle Combination Truck Constant-Speed Oil Consumption
1 Condition GR > 0 and AES < 45
Equation CSOC=exp(3.920.661×ln(AES)0.01718×GR2+0.361×GR0.000640×AES×GR)
2 Condition GR > 0 and 45 AES 70
Equation CSOC=78.59+0.003813×AES221.76×ln(AES)+2.1254×GR0.0109×AES×GR
3 Condition GR > 0 and AES > 70
Equation CSOC=78.59+0.003813×AES221.76×ln(AES)+1.41×GR
4 Condition (min(1.5,AES/12.5) < GR 0) or (GR 0 and AES 70)
Equation CSOC=20.2+0.0000724×AES30.01034×AES2+0.662×AES8.52×ln(AES)
5 Condition otherwise
Equation CSOC=exp(1.85+0.000458×AES20.0746×AES0.0336×GR20.638×GR)
E.8.3 Constant-Speed Tire Wear (CSTW)
Table E-69. 3-4 Axle Combination Unit Truck Constant-Speed Tire Wear
1 Condition GR > 3
Equation CSTW = 0.27453 0.016411×AES +0.090845×GR+ 0.00035502×AES2 + 0.047978×GR2 + 0.0042709×AES×GR
2 Condition GR < 3
Equation CSTW = ABS(0.14758 + 0.01337×AES + 0.0040158×GR 0.000053182×AES2 + 0.052391×GR2 + 0.0044432×AES×GR)
3 Condition 3 GR 3
Equation CSTW = 0.15566 0.0058457×AES + 0.041763×GR + 0.00021374×AES2 + 0.056992×GR2 + 0.0050156×AES×GR
E.8.4 Constant-Speed Maintenance and Repair (CSMR)
Table E-70. 3-4 Axle Combination Unit Truck Constant-Speed Maintenance and Repair
1 Condition 3 GR 1 and AES (7.5×GR2 52.5×GR 25) and AES < (7.5×GR2 52.5×GR 20)
Equation CSMR = 169.6 + 6.4867×AES + 333.98×GR + 48.825×GR2
2 Condition (GR > 1) or (GR < 1 and GR 3 and AES (7.5×GR252.5×GR20))
Equation CSMR = 46 + 0.008×AES2 + 0.146×AES×GR
3 Condition Otherwise
Equation CSMR = 2.44881 0.0404901×AES(1.5) 15.8112×GR
E.8.5 Constant-Speed Depreciation (CSVD)
Table E-71. 3-4 Axle Combination Truck Constant-Speed Vehicle Depreciation
1 Condition AES<55
Equation CSVD=0.354+0.000974×AES0.0806×ln(AES)
2 Condition otherwise
Equation CSVD=0.05657+1.598/AES
E.8.6 Excess Fuel Consumption Due to Speed Variability (SCCFC)
Table E-72. 3-4 Axle Combination Unit Truck Excess Fuel Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCFC=0.324×CSMAX2
2 Condition CSMAX 5
Equation SCCFC=6.342+0.5855×CSMAX+0.03191×CSMAX2
E.8.7 Excess Oil Consumption Due to Speed Variability (SCCOC)
Table E-73. 3-4 Axle Combination Unit Truck Excess Oil Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCOC=0.00136×CSMAX2
2 Condition CSMAX 5
Equation SCCOC=exp(4.408+0.6632×ln(CSMAX)+0.000148×CSMAX2)
E.8.8 Excess Tire Wear Due to Speed Variability (SCCTW)
Table E-74. 3-4 Axle Combination Unit Truck Excess Tire Wear Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCTW=0.0008×CSMAX2
2 Condition CSMAX 5
Equation SCCTW=exp(7.111+2.0276×ln(CSMAX)0.000102×CSMAX2)
E.8.9 Excess Maintenance and Repair Due to Speed Variability (SCCMR)
Table E-75. 3-4 Axle Combination Unit Truck Excess Maintenance and Repair Due to Speed
1 Condition CSMAX < 5
Equation SCCMR=0.0012×CSMAX2
2 Condition CSMAX 5
Equation SCCMR=exp(6.639+0.006003×CSMAX+1.912×ln(CSMAX))
E.8.10 Excess Depreciation Due to Speed Variability (SCCD)
Table E-76. 3-4 Axle Combination Unit Truck Excess Depreciation Due to Speed Variability
1 Condition CSMAX < 60
Equation SCCD=0.0002×CSMAX
2 Condition CSMAX 60
Equation SCCD=exp(5.007+0.000162×CSMAX2)
E.8.11 Excess Fuel Consumption Due to Curves (CFC)
Table E-77. 3-4 Axle Combination Unit Truck Excess Fuel Consumption Due to Curves
1 Condition DCA < 6 and AES 20
Equation CFC = MAX(0,( 0.069855 + 0.4852×LN(DCA) + 0.029223×LN(AES))/(1 0.30752×LN(DCA) + 0.10364×(LN(DCA))2 0.52169×LN(AES) + 0.10545×(LN(AES))2))
2 Condition 20 < AES (64 + 0.93749×DCA 13.928 × DCA(0.5)) and DCA < 6
Equation CFC = MAX(0, 36.549 + 8.3919×DCA + 19.444×LN(AES) 0.19172×DCA2 2.6623×(LN(AES))2 1.9932×DCA×LN(AES))
3 Condition 20 < AES (64 + 0.93749×DCA 13.928 × DCA(0.5)) and DCA 6
Equation CFC = MAX(0, 44.639 + 15.079×LN(DCA) + 31.738×LN(AES) 1.734×(LN(DCA))2 5.305×(LN(AES))2 3.6061×LN(DCA)×LN(AES))
4 Condition DCA > 1 and AES (67 + 0.93749×DCA 13.928 × DCA(0.5))
Equation CFC = MAX(0, EXP(948774.18 + 1.056802×(LN(DCA))2 + 11715.15×AES(0.5)×LN(AES) + 54041.58×(LN(AES))2 133443.12×AES(0.5) 268395.66×LN(AES) + 309522.12/LN(AES) 1311374.33/(AES(0.5))))
5 Condition DCA 1 and AES (67 + 0.93749×DCA 13.928 × DCA(0.5))
Equation CFC = MAX(0, (13.559 1.1956×DCA + 0.37772×DCA2 + 3.5166×LN(AES))/(1 0.37771×DCA + 0.1152×DCA2 0.1529×LN(AES)))
6 Condition Otherwise
Equation CFC = 0
E.8.12 Excess Tire Wear Due to Curves (CTW)
Table E-78. 3-4 Axle Combination Unit Truck Excess Tire Wear Due to Curves
1 Condition (DCA 16 and AES (0.02381×DCA2 1.4524×DCA + 42.143))
or (16 > DCA 6 and AES (35 125/DCA + 750/DCA2))
or (DCA < 6 and
AES (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3))
Equation CTW = MAX(0, 578653×EXP( EXP( (DCA 54.618)/20.44) (DCA 54.618)/20.44 + 1) × EXP( EXP( (AES 120.41)/37.427) (AES 120.41)/37.427 + 1))
2 Condition (DCA 16 and AES < (0.02381×DCA2 1.4524×DCA + 42.143))
or (16 > DCA 6 and AES < (35 125/DCA + 750/DCA2))
Equation CTW = MAX(0, 26.305 + 16.264×LN(DCA) + 20.114×LN(AES) 1.7217×(LN(DCA))2 3.4077×(LN(AES))2 4.0945×LN(DCA)×LN(AES))
3 Condition DCA < 6 and AES < (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3)
Equation CTW = MAX(0, 3.8937 + 3.8291×DCA + 0.092128×AES 0.22412×DCA2 0.00082522×AES2 0.064764×DCA×AES)
E.8.13 Excess Maintenance and Repair Due to Curves
Table E-79. 3-4 Axle Combination Unit Truck Excess Maintenance and Repair Due to Curves
* The third equation for 3-4 Axle Combination Unit Truck excess maintenance and repair due to curves is, under certain conditions, used to increment the CMR value derived from the second equation. Under some circumstances, the conditions for both equation two and equation three will be true.
1 Condition (DCA 17.5 and AES (0.4×DCA + 29.5))
or (17.5 > DCA 2.5 and AES (1.5×DCA + 48.75))
or (DCA < 2.5 and AES (4×DCA + 35)
Equation CMR = MAX(0, EXP(304.96 0.90108×DCA + 2.0321×DCA(0.5)×LN(DCA) 0.70003×LN(DCA) 41.773×LN(AES) 1312.1/AES(0.5) + 2080.7/AES))
2 Condition (DCA 3 and (6.667×DCA2 + 38.33×DCA + 22.5) AES (6.667×DCA2 38.33×DCA + 62.5))
or (3 < DCA 6 and AES 32.5)
or (6 < DCA < 10 and AES (2.5×DCA + 47.5))
or ((DCA 10 and AES (0.5×DCA + 27.5))
Equation CMR = 0.1
3* Condition (3.5 < DCA < 6.5 and 12.5 < AES < 22.5)
or (5.5 < DCA < 12.5 and 7.5 < AES < 17.5)
Equation CMR = CMR + 0.1
4 Condition Otherwise
Equation CMR = 0

E.9 5+ Axle Combination Unit Truck

E.9.1 Constant-Speed Fuel Consumption (CSFC)
Table E-80. 5+ Axle Combination Unit Truck Constant-Speed Fuel Consumption
1 Condition 3 GR 3
Equation CSFC = (1618.8 864.83×LN(AES) + 124.88×(LN(AES))2 + 32.087×GR)/(1 0.16247×LN(AES) 0.07074×GR + 0.011717×GR2 0.0011606×GR3)
2 Condition GR < 3
Equation CSFC = 305.94 + 76.547×LN(AES) + 2737.7/AES 5493.1×EXP(AES)
3 Condition GR > 3
Equation CSFC = (1607 986.23×LN(AES) + 149.01×(LN(AES))2 + 84.747×GR)/(1 0.17168×LN(AES) 0.021455×GR)
E.9.2 Constant-Speed Oil Consumption (CSOC)
Table E-81. 5+ Axle Combination Truck Constant-Speed Oil Consumption
1 Condition GR > 0 and AES < 55
Equation CSOC=exp(4.600.668×ln(AES)0.01879×GR2+0.394×GR0.000873×AES×GR)
2 Condition GR > 0 and AES 55
Equation CSOC=9.383+0.003478×AES0.271×AES+3.040×GR 3
3 Condition min(1.5,AES/15.0) < GR 0 and AES < 55
Equation CSOC=42.6+0.000189×AES30.0273×AES2+1.633×AES18.96×ln(AES)
4 Condition min(1.5,AES/15.0) < GR 0 and AES 55
Equation CSOC=9.383+0.003478×AES20.271×AES
5 Condition GR min(1.5,AES/15.0) and AES < 55
Equation CSOC=exp(2.52+0.000397×AES20.0675×AES0.0353×GR20.652×GR)
6 Condition GR min(1.5,AES/15.0) and AES 55
Equation CSOC=115.8+0.5094×AES37.27×ln(AES)3.064×GR
E.9.3 Constant-Speed Tire Wear (CSTW)
Table E-82. 5+ Axle Combination Truck Constant-Speed Tire Wear
1 Condition GR2.5 and AES < 55
Equation CSTW=exp(1.6+0.0000684×AES2+0.00608×AES+1.567×ln(GR)0.000762×AES×GR)
2 Condition GR2.5 and AES 55
Equation CSTW=1.122+0.000357×AES20.03264×AES+0.06295×GR2+0.005081×AES×GR
3 Condition (0.5 < GR < 2.5 and AES<15) or (AES/35 < GR < 2.5 and AES 15)
Equation CSTW=0.1432+1.248×106×AES3+0.0639×GR2+0.1167×GR+0.00332×AES×GR
4 Condition GR < AES/35 and AES max(15.,25×GR)
Equation CSTW=0.1283+1.442×106×AES3+0.01044×AES+0.208×GR2+0.01337×AES×GR
5 Condition otherwise
Equation CSTW=exp(3.051.5×106×AES30.01358×AES+2.13×ln(GR)0.001779×AES×GR)
E.9.4 Constant-Speed Maintenance and Repair (CSMR)
Table E-83. 5+ Axle Combination Truck Constant-Speed Maintenance and Repair
1 Condition GR 0
Equation CSMR=44.9+0.01148×AES2+0.254×AES×GR 2
2 Condition GR < 0 and AES > 25 and AES 40×GR15
Equation CSMR = 78.7+1.545×AES20.6×ln(AES)+0.254×AES×GR
3 Condition otherwise
Equation CSMR=0.9960.00149×AES215.8×GR
E.9.5 Constant-Speed Depreciation (CSVD)
Table E-84. 5+ Axle Combination Truck Constant-Speed Vehicle Depreciation
1 Condition AES < 55
Equation CSVD = 0.395+0.001215×AES0.0941×ln(AES)
2 Condition otherwise
Equation CSVD = 0.05657+1.598/AES
E.9.6 Excess Fuel Consumption Due to Speed Variability (SCCFC)
Table E-85. 5+ Axle Combination Truck Excess Fuel Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCFC=0.3584×CSMAX2
2 Condition CSMAX 5
Equation SCCFC=2.052+1.167×CSMAX+0.03292×CSMAX2
E.9.7 Excess Oil Consumption Due to Speed Variability (SCCOC)
Table E-86. 5+ Axle Combination Truck Excess Oil Consumption Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCOC=0.0028×CSMAX2
2 Condition CSMAX 5
Equation SCCOC=exp(3.735+0.6849×ln(CSMAX)+0.000112×CSMAX2)
E.9.8 Excess Tire Wear Due to Speed Variability (SCCTW)
Table E-87. 5+ Axle Combination Truck Excess Tire Wear Due to Speed Variability
1 Condition CSMAX < 5
Equation SCCTW=0.0012×CSMAX2
2 Condition CSMAX 5
Equation SCCTW=exp(6.643+1.947×ln(CSMAX)721×107×CSMAX2)
E.9.9 Excess Maintenance and Repair Due to Speed Variability (SCCMR)
Table E-88. 5+ Axle Combination Truck Excess Maintenance and Repair Due to Speed Variability
1 Condition Condition CSMAX < 5
Equation SCCMR=0.0012×CSMAX2
2 Condition CSMAX 5
Equation SCCMR=exp(6.705+0.008136×CSMAX+1.94×ln(CSMAX))
E.9.10 Excess Depreciation Due to Speed Variability (SCCD)
Table E-89. 5+ Axle Combination Truck Excess Depreciation Due to Speed Variability
1 Condition CSMAX < 60
Equation SCCD=0.0002×CSMAX
2 Condition CSMAX 60
Equation SCCD=exp(5.007+0.000162×CSMAX2)
E.9.11 Excess Fuel Consumption Due to Curves (CFC)
Table E-90. 5+ Axle Combination Unit Truck Excess Fuel Consumption Due to Curves
1 Condition DCA < 6 and AES 20
Equation CFC = MAX(0, EXP(4.892 5.8015/DCA2 0.070341×AES 6.612/AES(0.5)))
2 Condition 20 < AES (64 + 0.93749×DCA 13.928 × DCA(0.5))
and DCA < 6
Equation CFC = MAX(0, 0.76579 + 9.3637×LN(DCA) + 0.025171×AES 0.75491×(LN(DCA))2 + 0.00010068×AES2 0.22116×AES×LN(DCA))
3 Condition AES (64 + 0.93749×DCA 13.928 × DCA(0.5)) and DCA 6
Equation CFC = MAX(0, 44.672 + 15.308×LN(DCA) + 31.804×LN(AES) 1.8472×(LN(DCA))2 5.3075×(LN(AES))2 3.5085×LN(DCA)×LN(AES))
4 Condition DCA > 1 and AES (67 + 0.93749×DCA 13.928 × DCA(0.5))
Equation CFC = MAX(0, EXP(37.185 0.0034062×DCA2 + 1.262×(LN(DCA))2 0.00000046205×AES3 + 8.9915×LN(AES)))
5 Condition DCA 1 and AES (67 + 0.93749×DCA 13.928 × DCA(0.5))
Equation CFC = MAX(0, 3.3518 + 58.52/((1 + ((DCA 3.8448)/3.142)2) × (1+ ((AES 99.792)/14.486)2)))
6 Condition Otherwise
Equation CFC = 0
E.9.12 Excess Tire Wear Due to Curves (CTW)
Table E-91. 5+ Axle Combination Unit Truck Excess Tire Wear Due to Curves
1 Condition DCA 16 and AES (0.02381×DCA2 1.4524×DCA + 42.143))
or (16 > DCA 6 and AES (35 125/DCA + 750/DCA2))
or (1 DCA < 6
and AES (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3))
Equation CTW = MAX(0, EXP(40.193 + 14.371×EXP(DCA/53.803) + 1.2303×(LN(DCA))2 1.8886×AES/LN(AES) + 7.0737×AES(0.5)))
2 Condition DCA < 1 and AES (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3)
Equation CTW = MAX(0, 1/(1.1442 0.015388×DCA3 9704.3/AES(1.5) + 27917×LN(AES)/AES2 42372/AES2))
3 Condition (DCA 16 and AES < (0.02381×DCA2 1.4524×DCA + 42.143))
or (16 > DCA 6 and AES < (35 125/DCA + 750/DCA2))
Equation CTW = MAX(0, 27.686 + 18.235×LN(DCA) + 24.103×LN(AES) 2.2305×(LN(DCA))2 4.3932×(LN(AES))2 4.4593×LN(DCA)×LN(AES))
4 Condition DCA < 6 and AES < (23.334 + 112.5/DCA 150.83/DCA2 + 25/DCA3)
Equation CTW = MAX(0, 4.9124 + 4.8372×DCA + 0.12051×AES 0.2845×DCA2 0.0011691×AES2 0.08169×DCA×AES)
E.9.13 Excess Maintenance and Repair Due to Curves
Table E-92. 5+ Axle Combination Unit Truck Excess Maintenance and Repair Due to Curves
* The third and fourth equations for 5+ Axle Combination Unit Truck excess maintenance and repair due to curves are, under certain conditions, used to increment the CMR value derived from the second equation. These conditions for one or both of these equations may be true when the condition for equation two is true.
1 Condition (DCA 10 and AES (0.5×DCA + 32.5))
or (10 > DCA 3 and AES (2.8571×DCA + 56.071))
or (DCA < 3 and AES (6.6667×DCA + 27.5)
Equation CMR = EXP(703.2 + 0.75135×(LN(DCA))2 1.3433/DCA(0.5) 62.464×LN(AES) 2045.3/LN(AES) + 3128.1/AES))
2 Condition (1.5 DCA 3 and (5×DCA + 22.5) > AES > (5×DCA + 17.5))
or (16 DCA 25 and AES 17.5)
or (DCA > 25 and AES <= (1×DCA + 42.5))
or (3 < DCA < 16 and AES (1.5385×DCA + 42.115))
Equation CMR = 0.1
3* Condition (2.5 < DCA 6.5 and 12.5 AES 27.5)
or (3.5 < DCA 10.5 and 7.5 AES < 22.5)
or (9.5 DCA 15 and 2.5 < AES 17.5)
or (15 DCA 17 and 7.5 AES 17.5)
or (17 DCA < 22.5 and 7.5 AES 12.5)
Equation CMR = CMR + 0.1
4* Condition (3.5 < DCA < 6.5 and 17.5 AES < 22.5)
or (4.5 < DCA < 10.5 and 12.5 AES 17.5)
or (7.5 < DCA < 10.5 and 7.5 < AES 12.5)
Equation CMR = CMR + 0.1
5 Condition Otherwise
Equation CMR = 0

E.10 Pavement Condition Adjustment Factors

Pavement condition affects the 5 constant-speed operating cost consumption categories.
E.10.1 Constant-Speed Fuel and Oil Consumption (PCAFOC)
Table E-93. Fuel and Oil Consumption Pavement Condition Adjustment Factors
1 4-Tire Vehicles PCAFOC = 2.64+0.0729×PSR20.722×PSR
2 Trucks PCAFOC = 1.1760.1348×ln(PSR)
E.10.2 Constant-Speed Tire Wear (PCAFTW)
Table E-94. Tire Wear Pavement Adjustment Factors
1 4-Tire Vehicles PCAFTW = 2.401.111×ln(PSR)
2 Trucks PCAFTW = 1.668+0.001372×PSR30.581×ln(PSR)
E.10.3 Constant-Speed Maintenance and Repair (PCAFMR)
Table E-95. Maintenance and Repair Pavement Adjustment Factors
4-Tire Vehicles PCAFMR = 3.19+0.0967×PSR20.961×PSR
Single-Unit Trucks PCAFMR = 1.724+0.00830×PSR20.661×ln(PSR)
Combination Trucks PCAFMR = 2.075+0.273*PSR1.622×ln(PSR)
E.10.4 Constant-Speed Depreciation (PCAFVD)
Table E-96. Vehicle Depreciation Pavement Adjustment Factors
4-Tire Vehicles PCAFVD = 1.1360.106×ln(PSR)
Single-Unit Trucks PCAFVD = 1.3320.262×ln(PSR)
Combination Trucks PCAFVD = 1.320.254×ln(PSR)
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Updated: 02/14/2013