Study on the development of left turn lane front extension criteria at intersections

The extension of the left-turn lane in an intersection has the effect of increasing the intersection capacity in chronically congested areas.However, since left-turning vehicles wait inside the intersection, the turning angle of the left-turning vehicles becomes relatively small.However, if the length of the 'left-turn guidance lane' is too long, the left-turning turning radius in the intersection becomes smaller than the minimum turning radius of the vehicle, and the left-turning vehicle may leave the guidance lane.In this case, the possibility of conflict with the left-turning vehicle on the opposite side increases, which increases the possibility of traffic accidents.Therefore, the appropriate length of the left-turn guidance lane should be presented according to the intersection type (3-way, 4-way intersection) and road width.In this study, the appropriate length of the left-turn guidance lane according to the intersection type and the number of lanes on the main and secondary roads was calculated using the PC-CRASH simulation, and the effect of increasing the intersection capacity when the appropriate length of the left-turn guidance lane calculated