Speed limits

Use this section of the library to source research explaining the enormous contribution of speed to casualty rates. Increases in speed mean significant increases in casualties, even when speeds only rise a little bit. You can also browse here for research explaining why drivers say they speed.

Evaluating the safety impact of speed limits on rural highways in British Columbia
University of British Columbia, Vancouver, Canada, 20/07/2016

Changes in an area’s speed limit lead to an increase in death and serious injuries on the road, but after the immediate implementation these numbers will often reduce.

Dynamic traffic management on a familiar road: Failing to detect changes in variable speed limits
Ministry of Infrastructure and the Environment, The Netherlands, 02/02/2016

Study finds that drivers who are familiar with a route often fail to notice a speed-limit change.

Speed control with and without advanced warning sign on the field: An analysis of the effect on driving speed
Transportation Research Institute (IMOB), Belgium, 14/01/2016

Speed control in an unmarked police car with a mobile radar is particularly effective when combined with an advanced warning sign.

Driving behaviour responses to a moose encounter, automatic speed camera, wildlife warning sign and radio message determined in a factorial simulator study
Swedish National Road and Transport Research Institute, 19/11/2015

Wildlife signs and radio messages reduce driver speed, but not as much as encountering an unfenced moose.

GO 20: Towards changing the default urban speed limit to 20mph
Brake, the road safety charity, UK, 16/06/2015

A major research report calls for a reduction in the red tape and restrictions that prevent councils from introducing widespread 20mph limits in the UK.

Support and compliance with 20 mph speed limits in Great Britain
University of the West of England, 16/06/2015

Some drivers who agree with 20mph limits fail to comply with the limits, whereas some who are opposed to the limits do comply.

Go slow: an umbrella review of the effects of 20 mph zones and limits on health and health inequalities.
Durham University, 28/09/2014

20mph (32km/h) limits and zones are effective in reducing crashes, injuries, overall speeds, and traffic volumes.

Reduced speed threshold shows significant road safety gains
New Zealand Police, 11/04/2014

Up to 51% fewer New Zealand drivers broke the 100km/h (62mph) speed limit during two months when the enforcement threshold was temporarily lowered from 10km/h (6.2mph) to 4km/h (2.5mph).

Eight in 10 back 20mph limits
Brake and Allianz, 02/04/2014

Eight in 10 (78%) people in the UK think 20mph should be the default speed limit around schools, homes and shops.

Feet First – Improving Pedestrian Safety in London
London Assembly Transport Committee, 01/04/2014

Measures to improve pedestrian safety in London, including 20mph limits and extending crossing times on pedestrian crossings.

Lack of knowledge about lorry laws
AA DriveTech, 13/02/2014

81% of UK drivers do not know that trucks on single carriageway roads have a lower speed limit, leading to road rage and dangerous overtaking.

Variable speed limits cut Forth Bridge crashes
The Scotsman, 08/02/2014

Injury crashes on the Forth Bridge in Scotland dropped from 12 per year to two in the year following introduction of a variable speed limit.

Nine local actions to reduce health inequalities
British Academy, 10/01/2014

Introducing 20mph limits around homes, shops and schools is one of nine key local authority actions to improve public health.

Serious crashes fell 33% after the speed limit reduced from 90km/h to 70km/h in Belgium
Hasselt University, 14/05/2013

Fatal and serious injury crashes dropped 33% following speed limit reductions from 90km/h (55mph) to 70km/h (43mph) on highways in the Flemish region of Belgium.

Cutting the speed limit to 40km/h (25mph) on residential roads in Canada cut average speed
University of Alberta, 01/03/2013

Average speeds dropped 2.26km/h (1.4mph) when speed limits were cut to 40km/h (25mph) from 50km/h (31mph) on residential streets in Edmonton, Canada, enforced by speed cameras.

20mph limits boost economic and environmental sustainability of urban areas
University of Connecticut, 18/12/2012

Reducing injury risk to pedestrians and cyclists through 20mph limits boosts the economic and environmental sustainability of urban areas.

Speed limits: a review of evidence
RAC Foundation, 01/11/2012

Lower speeds reduce air and noise pollution, collisions and casualties and should be achieved through low limits and measures to control speed such as vehicle technology and enforcement.

RAC Report on Motoring 2012
RAC, 20/06/2012

87% of company car drivers in the UK admit to speeding on motorways compared to 61% of private drivers

Raising the UK motorway speed limit would have an adverse effect on health
London School of Hygiene and Tropical Medicine, 05/01/2012

Any economic benefits of raising the UK motorway speed limit by 10mph would be outweighed by the adverse health effects.

Negative impact of raising the UK motorway speed limit
Professor Rune Elvik, 25/12/2011

Raising the UK motorway speed limit to 80mph would result in at least 25 additional deaths and 100 serious injuries annually.

The effects of drivers’ speed on the frequency of road accidents
Transport Research Laboratory, 20/09/2011

The percentage reduction in accident frequency per 1mph reduction in mean speed has been shown to vary according to the road type and the average traffic speed.

The impact of 20 mph traffic speed zones on inequalities in road casualties in London
London School of Hygiene and Tropical Medicine, 15/11/2010

The targeting of 20mph zones to socioeconomically deprived areas has mitigated widening socioeconomic differentials in road injury in London, but differentials have still continued to widen overall.

The impact of lower speed limits in urban and metropolitan areas
Monash University Accident Research Centre, 01/03/2010

Lower urban speed limits have success in reducing casualties and gain community support and do not reduce journey time significantly.

Assessing community attitudes to speed limits: final report
Monash Accident Research Centre, 01/03/2010

A community's knowledge of speed-related risk correlates to their support for lower speed limits.

Effect of 20 mph traffic speed zones on road injuries in London, 1986-2006
London School of Hygiene and Tropical Medicine, 14/02/2010

Longitudinal research shows 20mph limits save lives and should be more widely implemented.

Improving road safety in urban areas
Parliamentary Public Accounts Committee, UK, 23/10/2009

20mph zones among other measures are recommended in this parliamentary committee report.

Road safety PIN (performance index) Flash 12 report
The European Transport Safety Council, 11/02/2009

Widespread 30kph zones and other measures used in Sweden would halve child deaths on European roads.

The effects of area-wide road speed and curvature on traffic casualties in England
Loughborough University, 01/01/2009

Increased average speed in a region leads to increased total fatalities and serious injuries.

Evaluation of the South Australian default limit
Centre for Automotive Safety Research, Australia, 01/01/2008

Casualties and speeds dropped as a result of the urban speed limit in South Australia being reduced in 2003 from 60km/h (38mph) to 50km/h (31mph).

Speed and road safety: Synthesis of evidence from evaluation studies
Transportation Research Board of the National Academies, 28/12/2006

Speed has a major impact on the number and severity of crashes and the relationship between speed and road safety is causal, not just statistical.

Car occupant and motorcyclist deaths 1994-2002
TRL, 01/04/2005

Dangerous driving, most notably excessive speed, is cancelling out developments in vehicle safety. The percentage of fatal crashes caused by dangerous behaviour and risk-taking has increased.

Raised speed limits, speed spillover, case-fatality rates, and road deaths in Israel
Hebrew University-Hadassah, 01/01/2004

Raising a speed limit from 90 to 100 km/h resulted in increased speeds of 4.5%–9.1%. Over a five-year period there was a sustained increase in deaths (15%) and case fatality rates (38%).


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