Developing the Dynamic Bus Lane Using a Moving Block Concept

Abstract

Existing dynamic bus lanes (DBLs) typically use a fixed and long blocking space to guarantee bus priority, leading to a conflict between bus priority and traffic capacity. This study proposes an innovative approach in a connected-vehicle (CV) environment, called dynamic bus lane with moving block (DBLMB). The length of the moving block can be adjusted with the bus speed in real time, aiming to ensure bus priority with fewer road resources, thus improving traffic capacity. A three-lane cellular automata model is established to evaluate DBLMB in comparison with two other strategies, bus lane without priority and bus lane with intermittent priority (BLIP). First, the benefits of DBLMB over the established DBLs are analyzed qualitatively by the macroscopic fundamental diagram. Next, simulation experiments are conducted to compare the coordination between bus priority and capacity under different strategies. Then, the impact of DBLMB on microscopic traffic flow is investigated through evaluation indicators including lane density, lane speed, lane-changing frequency, and travel speed. Finally, the sensitivity of bus delay and traffic capacity to CV penetration is discussed. The results show that: (1) the capacity of a three-lane road adopting DBLMB strategy can be stabilized above 5200 passenger car units per hour (pcu/h) when the bus departure interval is higher than 60 s and the expected level of service is below B. (2) With 100%, 80%, 60%, 40%, and 20% of CV penetration, DBLMB improves the average capacity of the road by 523 pcu/h compared with BLIP, with only an incremental bus delay of 6.43 s per vehicle.