Citation

Ludwick JS. Transp. Res. Rec. 1975; 536: 1-10.

Copyright

(Copyright © 1975, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

An urban network traffic model has been modified to simulate a bus priority technique that automatically grants a green signal to buses as they approach an intersection. Such a technique could be implemented at individual intersections. Bus routes along 18th and 19th streets in downtown Washington, D.C., were simulated, and traffic data representing the morning peak were used as model input. Repeated simulation runs tested the effect that the bus priority system had on bus and nonbus traffic for combinations of bus headways (from 0.5 to 4 min) and near-side and far-side bus stop locations. The technique substantially improved many aspects of bus operations, including reduction of the mean number of unnecessary stops, and the mean, 90th percentile, and standard deviation of travel time. An improvement of 15 to 20 percent in bus travel time was supported by statistical test. Other vehicles on bus streets also benefited from this type of system. Cross-street traffic was adversely affected by shorter headways, but far-side stops were far superior to near-side stops under those conditions. Under the conditions simulated, the bus priority system would have the least impact on other vehicles in applications with far-side bus stops when headways were 2 min and greater. However, a consideration of passenger movement rather than vehicle movement may indicate that the system should be operated at shorter than optimum headways.