Abstract
The purpose of this paper is to propose a more accurate method for the estimation of the left-turn adjustment factor for protected left turns at traffic signals. Research on the left-turn adjustment factor for two-lane approaches with protected left turns from a shared lane, gave results that differ from those of the HCM. Based on extended field measurements, the model proposed in this paper relates the left-turn adjustment factor for protected left turns from a shared lane to a number of traffic parameters. Such as the distribution of vehicles in the lanes, the mean volume per lane and the proportion of the left-turning vehicles. (Author/publisher).