Title: Quantifying the Operational Performance of Left-Turn Lanes at Signalized Intersections: A Parametric Study
Abstract: Left-turning movements can significantly reduce the overall capacity of signalized intersections due to the queueing built up.Intersections with heavy left-turning volumes tend to use multiple lanes to accommodate left-turn movements, such as double and triple left-turn lanes.This study compares the potential impact of different left-turn configurations for saturated/near saturated levels.A signalized intersection located in the city of Doha, Qatar, is selected to be examined and evaluated.A microscopic simulation approach is used to replicate the existing conditions before implementing different traffic demands, left-turn bay configurations, and traffic control parameters.The results suggest that signalized intersections, in general, and left-turn movements, in particular, benefit from multiple left-turn lanes.However, the anticipated operational benefits vary depending on several factors, such as the demand for left-turn movements and the length of the left-turn bay.The findings obtained from this study could be helpful for planners and decision-makers to decide the type of left-turn lane treatment needed to increase the capacity for different conditions.This work can be extended to mathematically quantify the expected operational improvements at signalized intersections