Harnessing connected and automated vehicle technologies to control lane changes at freeway merge bottlenecks in mixed traffic

Abstract

This paper proposes three control strategies for lane-changing (LC) at a merge bottleneck to improve bottleneck throughput by mitigating voids and speed disturbances in mixed traffic using connected and automated vehicle (CAV) technologies. Strategy 1 is ‘gap closure’ control, where an LC vehicle and its follower are controlled to close the void (extra time gap ahead) induced by the LC and prevent a backward-propagating speed disturbance. Strategy 2 is ‘batch LC’, where a group of LC vehicles are controlled to line up along a kinematic wave to minimize the total voids. Strategy 3 is ‘gap redistribution’ control, where extra gaps of vehicles are redistributed to periodically create large enough gaps for disturbance-free insertions. In a general control framework, the three strategies are integrated in different combinations exploiting their complementary nature. A numerical analysis shows that certain combinations, such as Strategy 2 and 3, can be very effective for improving bottleneck throughput. The analysis reveals insights on leveraging CAVs to develop traffic management strategies and/or policies and therefore improve system performance.