Citation

Ingram GK. Transp. Res. Rec. 1977; 650: 59-66.

Copyright

(Copyright © 1977, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

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Abstract

Voluntary car-pool matching programs and improvements in transit services are two transportation control policies that have received wide support from environmentalists, energy-conservation groups, and the public. This paper presents estimates of how these two policies would affect vehicle kilometers of travel and automobile emissions in Boston, Los Angeles, Chicago, and Washington, D.C. Because the four cities differ widely in terms of their spatial structure and their transportation systems, the estimates should cover the range of impacts expected in many large cities. The results indicate that car pooling will reduce vehicle kilometers of travel and automobile emissions by roughly 0.1 percent if pessimistic responses to employer-based car-pool matching programs are used and by as much as 1.5 percent if optimistic levels of participation are used. Improvement in transit performance, represented as a 20 percent reduction in travel time, is projected to reduce vehicle kilometers of travel by 0.5 to 1 percent and automobile emissions somewhat less. Crude cost-effectiveness analyses suggest that voluntary employer-based car-pool matching programs are attractive even if they only reduce vehicle kilometers of travel by 0.1 or 0.2 percent. The costs of improved transit service are difficult to estimate, but some bus-lane proposals are likely to be cost effective. However, savings that result from reductions in vehicle kilometers of travel attributable to improved transit performance are unlikely to justify investments in fixed-rail systems.