Vehicle-Arrival Characteristics at Urban Uncontrolled Intersections

Abstract

Vehicle-arrival characteristics are an important input for evaluating the performance measures at urban uncontrolled intersections. In the present study an attempt is made to identify suitable probability distribution models for vehicle arrivals at uncontrolled intersections under mixed traffic conditions. Data consisting of traffic volume,composition, and speeds of various types of approaching vehicles were collected at number of intersections and analyzed using various statistical techniques. A speed variation factor is introduced, and a linear relationship between speed variation factor and traffic volume is observed. A multivariate distribution framework is suggested for vehicle arrivals at uncontrolled intersections under mixed traffic conditions. A Poisson distribution gives a close fit to vehicle arrivals, where the traffic volumes are less than 500 vehicles/hour/lane only. The multivariate distribution concept can be used for higher traffic volumes under mixed traffic conditions. Issues related to the applicability of the proposed probability models are briefly discussed.