OPERATIONAL EVALUATION OF BUS PRIORITY STRATEGIES

The primary objective of this study was to evaluate the impact of the use of two bus priority techniques on the operation of bus and nonbus traffic in a simulated environment. The strategies studied were (a) contra-flow bus lane on a downtown street and (b) signal settings based on minimizing passenger instead of vehicle delays. The operational setting reflected actual observations on a Chicago downtown street where a contraflow bus lane was installed in the summer of 1980. It was found that predicted bus operation improved significantly as a result of dedicating an exclusive lane to bus traffic, as demonstrated by an increase in overall bus speed on the route. The signal priority technique implemented by means of the TRANSYT-7F model enhanced bus operation even further. The degree of bus operation improvement, however, was dependent on whether the buses operated in mixed traffic or on exclusive lanes. It was also noted that total vehicle-miles of travel for nonbus traffic decreased after the implementation of the bus lane. Some improvements in nonbus traffic operation on the study section may be attributed to that factor. Finally, a limited field study was conducted to test bus performance indices predicted by the TRANSYT model. The observed and simulated overall bus travel speeds were found to compare favorably at the 5 percent significance level.