Fundamental Relationships for Traffic Flows at Signalised Intersections

Abstract

This report presents findings of a study of fundamental traffic characteristics at signalised intersections based on surveys of queue discharge headways and speeds for individual vehicles and jam spacings at eighteen intersections in Sydney and Melbourne. Exponential queue discharge flow, headway and speed models are given. Other traffic parameters considered are spacing, gap length, density, gap time, occupancy time, space time, occupancy ratios, queue clearance wave speed, departure response time, saturation flow rate, start loss and end gain times. The report presents basic material on fundamental traffic flow relationships, describes the survey methodology, survey site characteristics, data processing, analysis method, calibration method, and presents calibration results. Results on uninterrupted flow models and downstream queue interference at paired intersections are presented. Implications of findings on capacity and performance modelling and adaptive signal control practice are discussed. Relationships for use in practice are given.