Claire E McKnight

BRIDGE AND TUNNEL TOLL ELASTICITIES IN NEW YORK: SOME RECENT EVIDENCE

In 1992, the authors carried out a statistical analysis of Triborough Bridge and Tunnel Authority (TBTA) crossings in New York City, to determine the impact of toll increases on traffic volumes and revenue. Using twelve years of monthly time-series data, we developed a set of multiple regression models that estimated traffic volumes on each TBTA bridge and tunnel as a function of the toll level and other explanatory variables. In most cases, the estimated toll elasticities were negative and much less than 1.0 in absolute value; the median toll elasticity for automobiles was found to be −0.10. Our finding that automobile travel demand is highly inelastic with respect to toll rates is consistent with most previous travel demand studies.

Impact of Traffic Congestion on Bus Travel Time in Northern New Jersey

Traffic congestion in Northern New Jersey imposes a substantial time operational penalty on bus service. The purpose of a project was to quantify the additional travel time that buses need because of traffic congestion. A regression model was developed to estimate the travel time rate (in minutes per mile) of a bus as a function of car traffic time rate, number of passengers boarding per mile, and the number of bus stops per mile. The model was used to estimate the bus travel time rate if cars were traveling under free-flow conditions, and the results were compared with the observed bus travel times.