Improving the Operational Efficiency of Buses With Dynamic Use of Exclusive Bus Lane at Isolated Intersections

The allocation of exclusive bus lanes is a strategy for giving priority to buses and improving the efficiency of the urban transportation system. However, in the traditional exclusive bus lane (TBL) design, only the through bus can be prioritized. This paper presents a dynamic exclusive bus lane (DBL) design, in which the exclusive bus lane at the exit can be dynamically used for the left turn buses and the opposing through buses during the various periods of a signal cycle. A median opening along with a pre-signal are set upstream of the intersection to control the permission of the left turn buses entering the opposing exclusive bus lane. An optimization model is formulated as a mixed-integer nonlinear program, into which the lane markings, signal timings, and location of the median opening are integrated. The average person delay of the intersection is used as the objective for balancing the performance of buses and private vehicles. The results from the case study and extensive numerical analyses reveal the promising properties of the DBL design for reducing the average person delay. As compared with the TBL design, a reduction in the average person delay of more than 10% can be achieved when the volume in a leg is greater than 900 veh/h, the left turn proportion is greater than 0.1, and the bus proportion is greater than 0.05. Moreover, using the DBL design can reduce the threshold of the allocation of the exclusive bus lane.