Designated bus lanes are those restricted to buses either permanently or during certain hours of the day. They are usually indicated with “Bus Only” posted signs along the route with specific regulations and/or are painted red. Dedicated bus lanes allow buses to bypass traffic congestion and avoid vehicular conflicts in mixed travel lanes which helps to improve bus service reliability. Implementation of these lanes can help increase the attractiveness of bus transit, thereby encouraging the mode shift from using single occupancy vehicles to buses.
On the other hand, the installations of dedicated bus lanes often disrupt existing traffic patterns which may result in delays and violations by other vehicles. Violations may include deliberately traveling in bus lanes (by other vehicle types), right turns in front of buses and parking in bus lanes, among others. These traffic violations may result in delays and obstruction of bus operations, impacting the performance of the roadway and potentially creating safety issues.
Siddique and Khan (2006) conducted a study to investigate the capacity of Bus Rapid Transit (BRT) corridors in Ottawa, Canada. The study focused on throughput of transit buses under prevailing conditions and compared it to the microsimulation incorporating 2021 traffic conditions. The results showed that that at saturated conditions with interference from other road users including turning vehicles at intersections, the average speed dropped by 75% and total bus delays and bus travel time increased by 135% and 96% respectively. However, they noted that the bus delays and increased dwell times could be due to the manual fare collection and operation of high-floor buses. However, the research did not assess the control delays of all the vehicles on individual lane groups at the intersections where the bus lanes were present.
Chen et al (2014) investigated the interactions between the general traffic flow and buses operating in exclusive bus lane and found that there was a traffic saturation reduction of 16% with a 17% increase in bus travel time. However, the study was focused only on one BRT corridor and was not conducted for two scenarios (before and after the implementation of BRT).
This research seeks to evaluate the impact on the performance of transit buses and intersection performance (and individual lane assessment) on corridors with dedicated bus lanes in Washington, DC. A “before” and “after” study approach will be used.
Associate Professor, Civil & Environmental Engineering Department
Director, Transportation Research Center
2300 Sixth Street NW
Washington, DC 20059
U.S. Department of Transportation, Office of the Assistant Secretary for Research and Technology – $250,000