Measuring Improvements in the Movement of Highway and Intermodal Freight
reflects freight performance, but not solely in relation to the highway system. It also only reflects costs, not the quality of service.
Data are available for cost of highway freight per ton-mile from the Financial and Operating Statistics (F&OS) maintained by the American Trucking Associations (ATA). The total cost measure can be taken directly from the F&OS. One of the primary strengths of this measure is that data on costs and ton-miles can be taken from the same source, which ensures that the data are comparable.
Fuel Consumption of Heavy Trucks per Ton-Mile
This measure is not easy to grasp as an indicator of freight performance. Although the measure itself is comprehensible, the link between fuel consumption and freight productivity is not readily apparent to the public.
If the interest is in the impact of the highway system on truck costs, fuel consumption per ton-mile is technically appropriate because it strips out the effects of drivers’ wages and fuel prices, both of which affect cost and neither of which depends on highway performance. Fuel consumption is affected, in part, by highway conditionsespecially congestion. Fuel consumption per ton-mile is also, of course, affected by changing technology of engines and fuels. Whether it would be possible to find some effective way to normalize for changing technology is an open question.
Fuel costs are available from the ATA’s Financial and Operating Statistics (F&OS). In order to extract fuel consumption, one would need to develop an average fuel price (most likely for diesel fuel). Alternatively, one could use data from FHWA’s Highway Statistics on fuel consumption by single-unit 2-axle 6-tire or more trucks. These data are derived from state fuel tax records and may not be comparable to figures on ton-miles (e.g., they may reflect impacts of improved tax compliance, improved reporting methods, or other factors).