A Cooperative Optimization Model for Variable Approach Lanes at Signaled Intersections Based on Real-Time Flow.

Area of Science:

• Traffic Engineering
• Transportation Science
• Urban Planning

Background:

• Traffic congestion at intersections is a major urban challenge.
• Imbalanced traffic flow exacerbates delays and reduces intersection efficiency.
• Existing traffic signal control methods may not adequately address variable traffic demands.

Purpose of the Study:

• To develop an optimized traffic signal control scheme for intersections.
• To minimize average vehicle delay and queue length.
• To enhance intersection capacity and efficiency using variable approach lanes (VALs).

Main Methods:

• Establishing a model for average delay deviation with delay minimization as the objective.
• Investigating threshold conditions for setting VALs based on traffic flow ratios.
• Developing an optimal timing method based on an improved Webster's formula.
• Comparing proposed scheme with existing methods using a real-world intersection case study.

Main Results:

• Determined threshold conditions for adjusting VALs based on left-turn traffic ratios (0.20-0.28).
• Proposed an optimal timing method considering delay, queue length, and capacity.
• The cooperative optimization scheme reduced travel time by 18.7% and improved efficiency by 9.9% compared to original and Webster's schemes.

Conclusions:

• Variable approach lanes (VALs) can be effectively utilized for traffic signal optimization.
• The proposed cooperative optimization scheme offers significant improvements in intersection performance.
• This approach provides a practical solution for mitigating intersection congestion and enhancing urban mobility.