Evaluation of delay in permitted left turn lane group in signalized intersection

In Signalized Intersection when left turn movement is in permitted phase, accident and crash possibility of this movement and through movement of opposing approach increases. In this research, according to capacity equations of permitted left turn in HCM, permitted left turn delay is determined in different conditions such as different left turn volumes, different through volumes in opposing approach, different number of through lanes in opposing approach, and different effective green ratio(g/C). In this research, in addition to evaluate effect of different parameters on permitted left turn delay, for each condition of different green ratio(g/C) and different number of through lanes in opposing approach(Nopp), critical boundary is defined. By this critical boundary, can select appropriate phasing between permitted or protected left turn phase.