Changes in the costs of owning and operating vehicles (trucks as well as cars) resulting from a transportation improvement project are counted as benefits or disbenefits.
- Roadway capacity expansion reduces congestion delay which reduces fuel costs.
- Pothole repairs and street resurfacing reduces vehicle wear.
- Improvements to alternative modes (walking, cycling, ridesharing and public transit) on a corridor allows some travelers to reduce their automobile travel, decreasing vehicle operating costs.
- Transit-oriented development allows some households to reduce their vehicle ownership, providing ownership cost savings.
Vehicle operating costs refer to costs that vary with vehicle usage, including fuel, tires, maintenance, repairs, and mileage-dependent depreciation costs (Booz Allen & Hamilton, 1999). Projects that alter vehicle miles traveled, traffic speed and delay, roadway surfaces, or roadway geometry may affect travelers' vehicle operating costs, which should be considered in a benefit-cost analysis. Vehicle ownership costs refers to fixed costs that are not directly affected by vehicle mileage, including time-dependent depreciation, insurance and registration fees, financing, and residential parking. Projects that change per capita vehicle ownership rates, such as significant changes in the quality of alternative modes and land use accessibility, may affect vehicle ownership costs, which should be considered in benefit-cost analysis.
- Estimate changes in total vehicle miles traveled along a corridor.
- Estimate changes in vehicle travel speeds and delay due to road and traffic conditions.
- Estimate fuel consumption rates, fuel prices, and non-fuel-related operating costs.
- Calculate total changes in vehicle operating costs.
- For improvements to ride quality, such as pothole repairs and curve or grade reductions, estimate effects on vehicle wear.
- Estimate changes in per capita vehicle ownership in an area.
- Estimate average vehicle ownership costs.
- Calculate total changes in vehicle ownership costs.
Factors Affecting Vehicle Operating Costs
The following factors affect vehicle costs (Booz Allen & Hamilton, 1999; Litman 2009; Polzin, Chu and Raman, 2008):
- Vehicle Type — Ownership and operating costs vary by vehicle size, class, and other characteristics. Trucks typically have much higher vehicle costs than cars.
- Vehicle Speed — Vehicle speed is the dominant factor affecting vehicle operating costs. Typically operating costs decrease with increasing speed to a certain point, and then begin to increase with increasing speed.
- Speed Changes — Changes in speed (also known as speed cycles) increase vehicle operating costs. This added cost is higher when speed cycling occurs at higher speeds.
- Gradient — Grades can be either positive (uphill) or negative (downhill). Positive grades are more demanding on vehicle engines and require greater fuel consumption. This leads to an increase in operating costs. Negative grades may reduce operating costs, but may also increase wear on brakes.
- Curvature — A highway curve requires a greater output of energy from a vehicle to counter the centrifugal force. This, combined with additional wear on the vehicle's tires, leads to an increase in operating costs.
- Road Surface — The roughness of the road surface can affect vehicle operating costs by affecting rolling resistance. Rough surfaces can reduce speed, require greater fuel consumption, increase wear on tires, and increase maintenance costs.
The Vehicle Operating Costs Methodology section discusses how to evaluate the benefits associated with a change in vehicle operating costs.
Booz-Allen & Hamilton Inc. (1999), California Life-Cycle Benefit/Cost Analysis Model (Cal-B/C)—Technical Supplement to User's Guide, California Department of Transportation; at http://www.dot.ca.gov/hq/tpp/offices/ote/benefit_files/tech_supp.pdf.
Todd Litman (2009), “Vehicle Costs,” Transportation Cost and
Benefit Analysis; Techniques, Estimates and Implications, Victoria
Transport Policy Institute (www.vtpi.org); at www.vtpi.org/tca/tca0501.pdf.
Steven E. Polzin,
Xuehao Chu and Vishaka Shiva Raman (2008), Exploration
of a Shift in Household Transportation Spending from Vehicles to Public
Transportation, Center for Urban
Transportation Research (www.nctr.usf.edu); at www.nctr.usf.edu/pdf/77722.pdf.
World Bank (2006), Road
Software Tools, The World Bank Group (www.worldbank.org); at www.worldbank.org/transport/roads/tools.htm.