Citation

Khasnabis S, Rudraraju R. Transp. Res. Rec. 1997; 1603: 128-136.

Copyright

(Copyright © 1997, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

10.3141/1603-17

PMID

unavailable

Abstract

Preemption techniques are designed to provide preferential treatment for buses at signalized intersections. A preemption strategy, if properly designed, can provide continuous green phases for buses at successive intersections, thereby reducing travel times and delays along the bus route. However, the length of delay incurred by all the vehicles in the system may be affected by the different bus headways under preemption operation. Unfortunately, no formal technique is available to assess the cumulative delay consequences of bus headways. The application of a simulation model, NETSIM, to test the effect of different headways is presented. NETSIM was selected because it can microscopically simulate vehicular movements on a street network and because an animation feature within NETSIM is available that allows the user to track an individual vehicle from the source to the sink. A major bus route in Ann Arbor, Michigan, was used as the experiment site. The major conclusions are that NETSIM can generate delay data at various levels of aggregation (e.g., link, node, and route) that can be used to assess the operational consequences of bus headways under preemption conditions. For the volume levels studied in the project, the savings in delay along the bus route resulting from preemption appears to be a good measure for determining the optimum headway.

Language: en