Delay to major-street through vehicles due to right-turn activity

This paper describes a model for predicting the delays to major-street through drivers due to vehicles turning right from the outside through traffic lane on the major street. The accuracy of this model was verified with results reported in the literature and with a widely-used microscopic traffic simulation model. A sensitivity analysis using the model indicated that through vehicle delays due to right-turn activity may typically range from 0.0 to 6.0 s vehicle^–1. This delay increased with increasing flow rate in the outside lane, increasing major-street speed, an increase in the portion of right-turns, or a decrease in the right-turn speed. A case is made that, while the average delay to through vehicles may be relatively small, the total delay incurred by the through stream can be quite large. In the context of improving overall operations at an unsignalized intersection, it may be appropriate to consider first those geometric improvements that could reduce right-turn-related delays to the major-street through movement.