opinion surveys could also provide insight into issues such as privacy concerns. Specific attention should be given to sample design to ensure that it captures those most affected (for good and ill), but also to ensure that the sample in the aggregate is representative of users of the facility.

Careful and extensive evaluation of early congestion pricing programs is critical to developing a better understanding of the advantages and disadvantages of this policy. An appropriate evaluation of a congestion pricing project must be designed carefully to account for different explanations of the possible outcomes other than the introduction of a congestion fee (Campbell and Stanley 1966; Weiss 1972). Considerable data must also be collected. The evaluation outlined in this chapter could easily extend over several years and cost $5 to $10 million. The costs would be high, but it would be a worthwhile public investment. Congestion wastes billions of dollars in metropolitan areas every year, and it has persisted despite the expenditure of many billions of dollars to expand highway and transit capacity. Many of the transportation control measures being considered and implemented to meet clean air standards are estimated to have quite modest effects on travel (Deakin 1993). Despite its political challenges, congestion pricing has more promise than most other policies for significantly reducing congestion. The expense of a few million dollars to demonstrate the potential of the theory would be a good social investment.

Although many of the most important questions about congestion pricing —the time savings and potential adverse impact on the poor—can only be answered through evaluation of actual projects, there are issues and questions about congestion pricing that deserve further exploration independent of any project actually going forward.

In examining the possible impact of congestion pricing on business activity and commercial transportation in the United States, the committee found no prior studies to inform its analysis. Given the importance of transporta-

Front Matter (R1-R10)

Executive Summary (1-15)

1 Introduction (16-26)

2 Theory and Experience (27-38)

3 Possible Effects (39-57)

4 Technical and Political Feasibility (58-80)

5 Design, Evaluation, and Research (81-96)

6 Summary (97-103)

Appendix A: Traffic Congestion (104-116)

Appendix B: Theory, Experience, and Estimated Effects (117-139)

Study Committee Biographical Information (140-146)