Determine Lane Function of Variable Approach Lane at the Signalized Intersection Based on Real-time Traffic Status

How to determine the lane function of Variable Approach Lane (VAL) is critical for satisfying the turning traffic demand and decreasing vehicle delay. Though a lot of scholars have studied this topic, most of them ignore the cycle-by-cycle traffic demand fluctuation at a signalized intersection. This paper proposes a dynamic offline lane assignment scheme to determine the lane function of VAL based on real-time traffic status identification. Firstly, the Fuzzy C- Means Algorithm is utilized to identify the traffic status based on three indicators: volume, occupancy, and speed in a cycle. Then, a rapid traffic status identification system focusing on through and left-turn traffic is built. A dynamic lane assignment model is established to determine the lane function of VAL in a real-time manner. An example is introduced to better illustrate how the method works. The result shows that the number of vehicles released increases by 9.8% while the delay per vehicle is reduced by 9.2%. In addition, the performance of dynamic lane, fixed left-turn lane, and fixed through lane under different traffic volumes is compared and results show dynamic lane has the best performance. Finally, this paper compares the proposed dynamic lane optimization method with two other optimization methods. Results reveal that the proposed method works better.