Indirect Transportation Energy

Construction, maintenance, and operation of transportation infrastructure and vehicles represent a substantial energy investment. This indirect energy consumption per vehicle kilometer was estimated for auto, bus, and rail transit through an energy investment analysis. Initially, total construction and manufacturing energy were converted to annual energy by assuming a service life. The annual operations and maintenance energy were added to this amount to obtain the total annual facility energy consumed. The total energy per vehicle kilometer was then derived based on observed levels of traffic on each type of road and transit facility. Finally, the vehicle manufacturing energy was added to obtain a grand total estimate of the megajoules per vehicle kilometer. The resulting modal energy estimates in megajoules per vehicle kilometer were: Freeways, 1.368; arterial streets, 1.525; 2‐lane roads, 1.582; trolleybuses, 1.503; diesel buses, 1.568; at‐grade street car, 10.778; commuter rail, 14.154, and subway, 22.636. The indirect energy associated with rail transit facilities is sizable both in absolute terms, and as a proportion of the total energy consumed. It should be carefully estimated and must be included in modal energy intensity analysis.