UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Influence of flow variation on fixed-time signal control

Martins Ribeiro, PC; (1992) Influence of flow variation on fixed-time signal control. Doctoral thesis (Ph.D), UCL (University College London). Green open access

[thumbnail of Martins_Ribeiro_10123400_thesis.pdf]
Preview
Text
Martins_Ribeiro_10123400_thesis.pdf

Download (8MB) | Preview

Abstract

The purpose of this thesis is to analyze the effects of fluctuation in traffic flows on the operation of fixed-time control systems. In the development of fixed time plans for area traffic control, traffic volumes reflecting average conditions for the movements at all intersections are normally required. Calculations made on basis of these values commonly overestimate the benefits of the implementation of fixed-time signal control plans because the variability of flows is not taken into account. The day-to-day, or between-days variation of traffic, is not normally considered in fixed-time plans and the daily systematic fluctuation, or within-day variation of traffic, is handled by the adoption of one of several possible procedures. In practice, single observations of flow are commonly used in place of the mean, and flows in different parts of the same network are sometimes observed on different days. The consequences of this practice are analyzed in view of the variability of traffic flows. In this thesis an analysis of the techniques currently available to handle traffic fluctuation by fixed-time control systems is made. Ways are investigated in which some measure of variability of traffic flows can be respected in the calculation of fixed-time signal plans. A method that incorporates the variability of the traffic flows in the calculation of a single fixed-time plan is developed. This was based on theoretical values and validated with real flows, collected in a purpose-specific field survey. The technique developed in this research has been found to improve the efficiency of the fixed-time systems in handling both of these kinds of variation. Using explicit conditions of a variety of traffic flows on each link, this technique is suitable to be used as a standard feature for calculation of fixed-time signal plans which will be used under a range of traffic conditions. The problem of the cycle time selection is analyzed and comparisons are made between the performance of the network, using cycle times suggested by the approximate method incorporated in TRANSYT, and those selected on the basis of full day by day optimisation by this program.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Influence of flow variation on fixed-time signal control
Open access status: An open access version is available from UCL Discovery
Language: English
URI: https://discovery.ucl.ac.uk/id/eprint/10123400
Downloads since deposit
41Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item