Empirical Analysis of Pricing Structure of Toll Facilities Based on Social Costs of Driving by Vehicle Class and Its Effects on Traffic, Toll Revenue,

Hiroyuki Iseki

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This study develops an analytical method to obtain toll rates for thirteen vehicle classes for seven
toll facilities in Maryland, taking into account various social costs of driving automobiles. The
model is comprised of two parts: (1) an equilibrium model to obtain non-peak period tolls that
incorporates capital and maintenance costs of toll facilities, vehicle emission costs, and
operating/maintenance costs incurred to vehicles due to uneven road surface, and (2) a model to
estimate optimal congestion tolls for three facilities that currently experience congestion. The
models are not a simple forward-moving model, but instead take into account the feedback
effects of revised toll rates on traffic volume and social costs of driving.
The analysis results show some expected results in the estimated tolls and their effects on
vehicle traffic, toll revenue, emission, and ESAL. While congestion tolls clearly show positive
effects across three facilities, results related to estimated non-peak period tolls and their effects
are not consistent across all facilities, depending on the relative magnitude of each social cost
factor as well as the relative levels of current tolls. Results from the sensitivity analysis
generally support the main results. These results reveal a lack of clear pattern in the current toll
structure in relation to vehicle classes among facilities, and indicate possible cross-subsidies
among facilities as well as among vehicle classes. Further research is warranted in order to
achieve road pricing schemes that are more efficient and equitable.