http://www.monash.edu.au/muarc/reports/muarc073.html

Red Light Running Behaviour at Red Light Camera and Control Intersections

Monash University Accident Research Centre - Report #73 - 1995

Authors: S. Kent, B. Corben, B. Fildes & D. Dyte
Abstract:

One of the key enforcement initiatives intended to reduce the number and severity of intersection crashes is Red Light Cameras. There are currently about 120 Red Light Camera intersections covering metropolitan Melbourne and Geelong. The objective of this study was to determine the nature and extent of red light running behaviour at a sample of camera and comparable non-camera sites around Melbourne. Signal compliance was measured as a function of speed zone, road cross section, lane type, time of day and day of week. Three intersections were investigated. For each intersection, measurements of red light running behaviour were obtained by video-taping traffic at three selected approaches, namely the camera approach, the opposite (non-camera) approach at the same intersection (i.e., subject to the red light camera ahead sign but with no camera) and also a matched approach with no signs or camera. Red light running was a relatively rare occurrence (123 encroachments out of 38,000 observed vehicle movements - 0.32%); Further, 93% of the encroachments occurred during the all-red period of the signal cycle when the probability of conflicting traffic is lowest. Red light running rates were significantly higher for right-tum movements compared to through movements. Red light running rates were also higher for right-tum movements in 60 km/h speed zones, on undivided roads than in 80 km/h speed zones on divided roads. The difference between right-tum and through movement red light running rates was most pronounced in the evening peak period. Notably, there were no differences in the observed rates of red light running between camera and non-camera approaches. Results are discussed in terms of their implications for further research and for the operation of the Red Light Camera Program in Victoria.
Executive Summary

Red light cameras have been in operation in Victoria since 1983 and currently cover about 120 signalised intersections in metropolitan Melbourne and Geelong. Cameras were originally introduced to reduce the incidence and severity of intersection crashes, particularly cross-traffic crashes.

While there have been some evaluations of the effectiveness of the Red Light Camera Program in reducing intersection crashes, there has never been a detailed study in Victoria of die nature and extent of red light running behaviour.

Thus, the prime objectives of this study were:

1. To examine red light running behaviour at a sample of Red Light Camera (RLC) sites in Metropolitan Melbourne and behavioural differences between RLC and Non-RLC sites (including non-camera approaches of RLC sites);

2. To investigate the effects of road cross section, speed zone, traffic volume, lane type and day of week on red light running behaviour;

3. To examine the relationship between red light running behaviour and crash occurrence at RLC sites in the light of the findings of a recent investigation of the effects of red light cameras on crash occurrence and types (Andreassen, 1995);

4. To make recommendations on future directions for the Red Light Camera Program in the light of the findings of the current study.

The study set out to examine red light running behaviour using the SCRAM computer-based network which controls traffic at most of Melbourne's signalised intersections. It was hoped that red light running behaviour could be efficiently measured via the SCRAM technology which relied on "trailing edge triggering" as vehicles cleared the magnetic loops prior to the intersection stop line. Extensive pilot testing using the SCRAM technology indicated that, in its current form, it was inadequate for the task for the following reasons:

1. There was under-counting of total hourly traffic volumes caused by vehicles queuing on the red phase with reduced headways (the detector loops were insensitive to short gaps between vehicles);

2. Over-counting of red light runners occurred in instances where vehicles stopped well over the stop line but did not proceed through the intersection;