Table 1: summary of transit signal priority deployment results

Pre-Deployment Impact Analysis

As part of planning, stakeholders should conduct a local impact analysis to assess the anticipated consequences of alternative EVP and TP strategies under consideration. Among those consequences may be the impact on traffic flow and vehicular and pedestrian safety. This local impact analysis may include site-specific surveys, empirical analyses and the use of microscopic simulation modeling tools such as CORSIM, INTEGRATION, VISSIM, PARAMICS, and MITSIM, which attempt to model the behavior of individual vehicles (Fujimoto & Leonard, 2001; Chang, Rahka, Dion, and Collura, 2003).

Based on a review of literature as part of this research project, the impacts of EVP and TP have been both positive and negative in more than a dozen actual EVP and TP project deployments in the U.S. and abroad. Moreover, simulation analyses reported in the literature review have produced results generally consistent with the impacts actually experienced in the project deployments. An overall observation made based on the literature review and the field tests conducted as part of this research project to date is that EVP and TP strategies can be integrated into conventional traffic signal control systems in an appropriate and desirable manner, provided that such integration is done with caution, that anticipated impacts are considered, and that the EVP and TP system and equipment are designed and installed properly.