A Technical Evaluation of Key Parameters Influencing Bus Priority at Signalized Intersections to Enhance Traffic Conditions: A Case Study of the Azar Bridge Intersection in Isfahan, Iran

Document Type : Original Article

Authors
Reza Shokouhi 1
Hooman Rahimi 2
Ali Naderan 3
1 Department of Civil Engineering, SR.C., Islamic Azad University, Tehran, Iran.
2 Department of civil Engineering, ShQ.C., Islamic Azad University, Shahr-e-Qods, Iran.
3 Department of Civil Engineering, SR.C .Islamic Azad University, Tehran, Iran.
10.22034/road.2026.588033.2510
Abstract
With increasing urbanization and traffic congestion—particularly under oversaturated conditions (V/C ≥ 1)—bus travel delays have become a major concern, reducing the appeal of public transportation. This study addresses the inadequacy of existing travel time models under heavy congestion, as most are developed for under-saturated conditions. A novel model is proposed and validated to estimate bus travel time at signalized intersections with actuated control, based on optimal detector placement and bus dwell time. Field data from two congested intersections in Isfahan were used. Simulation scenarios were developed using Aimsun and SCATS output to assess the impact of different detector locations and dwell times. Linear regression was used for initial predictions, followed by Gene Expression Programming (GEP) for optimization. The GEP model, incorporating optimal detector distance and dwell time, achieved high accuracy (R² = 0.99). However, exceeding threshold values for these parameters reduced model effectiveness. The findings suggest that dynamic signal control strategies, when optimized, can significantly reduce bus delays and enhance the reliability of public transit. The delay of buses reduced by 35% and overal delay reduced by 34%. Overally this model is recommended for use in planning and implementing Transit Signal Priority (TSP) systems.
Keywords
Aimsun
Priority
Detector
Dwell Time
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