A LOS-based signal compensation method for non-bus priority approach

TSP (transit signal priority) is an effective strategy to improve the transit performance at signalized intersection. However, TSP may have negative effect on vehicles in the non-priority direction. This paper proposed a rule-based signal control method: grant an optimal green compensation time to the non-priority direction which can reduce the vehicle delay in non-priority direction while make sure the vehicle delay in priority direction is limited in an acceptable level. This paper use LOS (level of service) as judging criteria to determine the compensation threshold and total compensation time. In addition, this paper introduced an installment compensation strategy, which can avoid the negative affect when compensation time is too long. Finally, the case study shows the optimized signal timing compensation plan will reduce 24.6% vehicle delay in non-priority direction and 29.8% in the entire intersection, the LOS of the intersection increase from E to D.