POTENTIAL BENEFITS TO TRANSIT IN SETTING TRAFFIC SIGNALS

Although it is common to optimize signal settings for fixed-time operation, this serves neither transit nor private vehicles adequately when their interaction is not considered appropriately in defining the total system. The TRANSYT model claims to account for transit operation along with private vehicles, but there are some potentially fatal flaws in its representation of mixed transit and private operation. However, incorporating additional modeling techniques can lead to more realistic representations. The resultant modeling formulation is applied to a 4-mi streetcar route in central Toronto to estimate an upper bound on the potential savings in streetcar delays due to setting traffic signals to accommodate streetcar operation. This is done by considering the idealized case where dwell times are kept constant at each given stop, varying only from stop to stop, so that a fixed-time traffic network can respond best to the streetcar arrivals. The potential gain may be worthwhile and practical effects, such as varying dwell times, should be incorporated into the modeling procedure.