Analyzing the Sensitivity of Transportation Performance Indicators to Headway Variations in Bus Rapid Transit

Bus Rapid Transit (BRT) is a quasi-mass-transit method that has received significant attention from urban managers and planners. Headway is one of the most influential parameters in this and other public transport methods. Generally speaking, a shorter headway reduces users’ waiting time and is perceived as a more favorable condition by the user. However, system managers might find it not so advantageous. Less research has been conducted on BRT's sensitivity analysis of the headway variable. This study analyzes the sensitivity of transportation performance indicators to headway variations in BRT using macroscopic model results and linear regression fitting (to parameters or coefficients). In addition, a simple yet practical performance indicator is proposed to determine the best headway. This study uses the information of the transportation master plan of Karaj, Iran (travel demand matrix and traffic samples from 2016(. The output of the fitted regression model indicates that the number of BRT passengers decreases by 58 for each one percent increase in headway. Also, the average trip time of the passengers increases by about 10 seconds for each minute increase in the headway. Our results show that the total amount of environmental pollutants in one hour during rush hours increase by 1228.7 kilograms for each minute increase in the headway. Finally, based on the proposed indicator, the optimal headway would be 5 minutes, as reducing the headway from 6 minutes to 5 minutes by purchasing a new fleet attracts 885 new passengers, the maximum value within the examined headways.