Transport CommitteeWritten evidence from Kenneth Todd

URBAN ROAD TRAFFIC SAFETY

Summary

The Memorandum Post Legislative Assessment of the Road Safety Act 2006, presented to the Transport Select Committee by the Secretary of State for Transport on July 2011, dealt primarily with the effects of driver behaviour on accidents. There is a need to evaluate how far the traffic control system contributes to unsafe behaviour by making drivers less attentive, more aggressive, and by diverting their attention from hazards. .

1. Accidents at major-minor road junctions

The urban major-minor road concept runs counter to basic safety principles: low speed and simple driver decisions. The most frequent and most severe type of accident at a major-minor road junction is the right-angle collision, usually blamed on the side-street driver’s priority violation. Priority rules diminish the responsibilities of the major-road driver, while maximising those of everyone who wants to cross. The major road makes motorists on it go fast without looking right or left, while the side-street drivers are given a highly complex task. They have to look right and left for pedestrians when entering, and again when exiting the junction, and also for two vehicle streams, one from the right and one from the left. The right-turner has to deal with yet another traffic stream, the one from the opposite direction — seven conflicts in all, with the elderly being the most vulnerable. It was said 70 years ago that our attention gets distracted from one conflict while we concentrate on another. The Road Safety Good Practice Guide (RSGPG) says driver decisions should be minimised. The danger and delay of crossing busy major roads has forced the taxpayers to pay billions for traffic lights, their manufacture, installation, operation and maintenance.

2. Accidents at traffic lights

Seen by the public as a safety device, the traffic light turned out to be one of those medicines that cures one disease and gives you another. It was known by the mid-1930s that traffic lights increased accident frequency.1 They compress an hour’s traffic into half an hour of green time and thereby halve all headways. They then make drivers go fast and keep close to the vehicle in front for fear of missing the green light, with their eyes up in the air rather than on the road. The combination of high speed, tailgating, diverted attention and sudden stops causes front-to-rear crashes. The Highway Code calls for moderate speed and extra care at junctions, and for safe following distance at all times. Like the priority of drivers on major roads, the traffic light encourages a disregard of the most elementary safety rules. The RSGPG says that traffic signals cause accidents to pedestrians, particularly in congested conditions, and advises that their use should be avoided where possible. An Australian study called signal-controlled intersections the most dangerous sites on the road.2

3. Remedies

The public is entitled to the safest, most efficient and most cost-effective form of traffic management. We might have thought that the traffic engineers would do their utmost to avoid the use of traffic lights and install safer, more efficient and more cost-effective alternatives. The mini- and other roundabouts are such alternatives and could replace most traffic lights. The DfT’s assessment in 2006 tells us that a mini-roundabout can improve capacity at overloaded junctions and act as an accident remedial measure.

4. Mayor Boris Johnson’s call for reducing the number of traffic lights in London received much publicity in May 2009 but only a timid reaction from TfL and most London Councils. We have seen no attempt by your Committee to enhance capacity or safety with the help of mini-roundabouts in urban areas. Nowhere in the Committee’s reports dealing with road safety do we find roundabouts mentioned, although their safety benefits have been proven over 40 years.

References

1 Harris, G “Modern Traffic Control.” Highways and Bridges, June 19, 1934, 6–9.

2 Ogden, K, et al Factors Affecting Crashes at Signalised Intersections. Monash University Accident Research Centre, 1994. Executive Summary.

October 2011

Prepared 18th July 2012