Estimating a congested road capacity – headway relationship of a multi-lane highway in an urban area based on lane position

This paper aims to estimate the road capacity based on the headway time to consider the road user behaviour which is the main element in microsystem of traffic analysis. The lane position is considered also in developing the capacity-headway model to reflect the driver behaviour in using each lane. Palestine Street in Baghdad City is chosen as the site study to simulate the urban multilane characteristics of roads. The data representing the roadway characteristics, vehicle volume, and headway time are collected at peak hours to reflect the high traffic flow level. The model is developed using regression analysis. The results show that the lane position affect the driver decision in choosing the lane of movement and affect significantly the capacity values especially the right lane position