Intended for healthcare professionals


Effectiveness of speed cameras in preventing road traffic collisions and related casualties: systematic review

BMJ 2005; 330 doi: (Published 10 February 2005) Cite this as: BMJ 2005;330:331
  1. Paul Pilkington, lecturer in public health (paul.pilkington{at},
  2. Sanjay Kinra, lecturer in epidemiology and public health medicine2
  1. 1 University of the West of England, Faculty of Health and Social Care, Bristol BS16 1DD
  2. 2 Department of Social Medicine, University of Bristol, Bristol
  1. Correspondence to: P Pilkington
  • Accepted 24 November 2004


Objectives To assess whether speed cameras reduce road traffic collisions and related casualties.

Design Systematic review.

Data sources Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials, Medline, Embase, Social Science Citation Index, TRANSPORT database, ZETOC, the internet (including websites of road safety and motoring organisations), and contact with key individuals and organisations.

Main outcome measures Road traffic collisions, injuries, and deaths.

Inclusion criteria Controlled trials and observational studies assessing the impact of fixed or mobile speed cameras on any of the selected outcomes.

Results 14 observational studies met the inclusion criteria; no randomised controlled trials were found. Most studies were before-after studies without controls (n = 8). All but one of the studies showed effectiveness of cameras up to three years or less after their introduction; one study showed sustained longer term effects (4.6 years after introduction). Reductions in outcomes across studies ranged from 5% to 69% for collisions, 12% to 65% for injuries, and 17% to 71% for deaths in the immediate vicinity of camera sites. The reductions over wider geographical areas were of a similar order of magnitude.

Conclusions Existing research consistently shows that speed cameras are an effective intervention in reducing road traffic collisions and related casualties. The level of evidence is relatively poor, however, as most studies did not have satisfactory comparison groups or adequate control for potential confounders. Controlled introduction of speed cameras with careful data collection may offer improved evidence of their effectiveness in the future.


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  • Contributors PP and SK developed the protocol. PP searched for studies and, together with SK, selected studies to obtain. PP and SK independently extracted data from each study. PP collated the data and drafted the report, with input from SK at all stages, including the calculation of relative risks. SG, BY, and LT made comments on the draft report. PP and SK finalised the review. PP is the guarantor.

  • Funding None.

  • Competing interests None declared

  • Ethical approval Not needed.

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