The design and performance of signal controlled intersections

Hounsell, Nicholas Brian (1989) The design and performance of signal controlled intersections. University of Southampton, Doctoral Thesis.

Abstract

This thesis describes research undertaken into the design and performance of signal controlled intersections in the U.K.with particular emphasis on the measurement and prediction of junction capacity. The research is based largely on analysis of data collected at over 70 signal controlled junctions throughout the country and on simulation modelling to investigate specific detailed aspects of traffic performance. The data collection techniques employed also allowed alternative data measurement and parameter calculation procedures which are commonly used elsewhere to be evaluated and biases inherent in certain procedures to be identified and quantified. Models for predicting saturation flow, a key determinant of capacity, are developed to cover individual and multi-lane entries both with unopposed traffic and with right turning traffic subject to opposing flow. For unopposed lanes, the main factors controlling saturation flow are lane width and position, gradient and, for lanes with turning traffic, the proportion of turning traffic and the radius of turn. For opposed lanes, these parameters are supplemented by the traffic flow to capacity ratio for the opposing entry and the storage space within the intersection for right turning vehicles. The relationships for multi-lane entries and opposed turning lanes show substantial departures from those traditionally used in the U.K. Other important determinants of capacity, lost time and passenger car equivalents, are also quanitified from the large database. A variety of site-specific factors which may influence junction capacity are also analysed and quantified where possible. These include the effects of diverging lanes and flared entries, lane choice considerations, bus lanes, bus stops and parked vehicles. Finally, the thesis contains a discussion of the main aspects of junction design and performance, including performance criteria, signal optimisation procedures, method of signal control and techniques for design and evaluation. Two aspects highlighted are junction design for minimum person delay, rather than the more usual vehicle delay criteria, and the use of the computer program OSCADY for design and evaluation.

This record has no associated files available for download.

Contributors

Download statistics