Transportation

In our analysis of automobiles, mass transit, active transportation, and other forms of transportation in an energy context, we looked at energy, greenhouse gas, and pollution implications of different transportation options. In this section we look at some wider impacts.

Cost

The following portrays the combined private and public cost per mile of transportation. While the full cost of driving is comparable to forms of mass transit on a per-passenger-kilometer basis, it is important to remember that car-oriented cities tend to be of lower population density and thus require greater amounts of travel.

Costs for bus rapid transit are calculated from the National Transit Database ¹, and other mass transit modes are calculated from the American Public Transportation Association ². The cost of driving is esimated from VTPI as detailed below, excluding the monetization of travel time to make a fair comparison with other modes, and assuming an average car occupancy of 1.67 people ³. Private costs of bicycle ownership are estimated from Litman ⁴, while the cost of roadway for walking and biking is estimated to be the same--per unit space required--as for driving, as estimated from the AFDC ⁵ and the Urban Institute ⁶.

Driving, however, carries significant costs that are pushed onto the general public as well as the costs the driver pays.

Source: Victoria Transport Policy Institute ⁷.

The presence of externalized costs may cause levels of driving in excess of the social optimum. The external costs can be internalized through carbon pricing, elimination of free parking and parking mandates, congestion pricing, and road tolling, among other policies.

Safety

Following are estimates of the death rates for modes of transportation.

Source: Federal Aviation Administration ⁸, Federal Highway Administration ⁹, Higgens ¹⁰, McFadden et al. ¹¹, Vehicle Technologies Office ³, Wang et al. ¹². Higgens reports deaths on a per-vehicle-trip, per-vehicle-hour, and per-vehicle-km basis, and the other sources are used to estimated vehicle load factors and convert figures to a per-passenger basis. McFadden et al. give a ferry capacity of 323, and we assumed that the actual number of passengers aboard is half that.

Most rail deaths in the United States are incurred by people who are on the tracks, either trespassers away from crossings or at crossings, and not on the trains themselves ¹³.

Road Damage

Larger vehicles tend to do more damage to roadways. The amount of damage is estimated as follows.

Road damage estimates can be traced to the AASHO Road Test ¹⁴, which found that damage grows with the fourth power of axle weight. The figures are imprecise, with actual damage depending on tire conditions, climate, type of pavement, and other factors ¹⁵. The ratio of damage done by a typical semi truck to a typical car, for instance, has been estimated at 9600 ¹⁶ or the 300s ¹⁵. Extrapolating results of the AASHO road test to vehicles smaller than passenger cars, which were not tested, is particularly uncertain ¹⁵. Sources: ¹⁷, ¹⁸.

Development triggers vehicle traffic which causes road damage. Estimates of appropriate pricing of this damage into the cost of development is as follows.

Figures for recommended development fees, based on roadway maintenance impacts, are compiled by RPI Consulting for Rio Blanco County, Colorado. Source: ¹⁸.