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Speed enforcement detection devices for preventing road traffic injuriesWilson C, Willis C, Hendrikz JK, Bellamy N
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SummaryDo speed enforcement detection devices (including speed cameras and radar and laser devices) reduce death and injury from road traffic crashes?Road traffic crashes are a major cause of death and disability. The speed at which a vehicle travels is an important determinant of injury; the faster the vehicle is travelling, the greater the energy inflicted on the occupants during a crash and the greater the injury. Excessive speed (driving faster than the posted limit or too fast for the prevailing conditions) has been found to contribute to a substantial number of crashes. It is predicted that, if the number of speeding drivers is reduced, both the likelihood and severity of a crash will be lowered. Therefore, interventions aimed at reducing traffic speed are considered essential to preventing road injuries. The implementation of SEDs (speed enforcement detection devices; including speed cameras and radar and laser devices) is one such measure. To evaluate the effectiveness of SEDs, the authors examined all eligible studies comparing areas before and after introduction of SEDs and their effect on road traffic crashes, injuries and speeding to areas with no SEDs. The authors found 26 studies, of which 21 measured the effect on crashes, all of which found a lower number of crashes in the SEDs area. In the vicinity of SED sites the reductions ranged from 14% to 72% for all crashes, 8% to 46% for injury crashes, and 40% to 45% for crashes resulting in fatalities or serious injuries. Effects over wider areas showed a crash reduction ranging from 9% to 35%, 7% to 30% for all injury crashes and 13% to 58% for crashes resulting in fatalities or serious injuries. The studies of longer duration showed that these positive trends were either maintained or improved with time. Despite the quality of the included studies being judged to be weak, the consistency of reported positive reductions in speed and crash outcomes across all studies suggest that SEDs are a promising intervention for reducing the number of road traffic injuries and deaths. However, higher quality studies using well designed controlled trials are needed to confirm this finding. As none of the studies were conducted in low-income countries, research in such settings is required. There is a need for consistency in methods, such as standards for the collection and reporting of speed and crash data, so that studies can be compared more easily. Studies should also continue careful data collection for lengthy follow-up periods after the installation of SEDs.
This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2009 Issue 2, Copyright © 2009 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
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April 19. 2006 AbstractBackgroundIt is estimated that by 2020, road traffic crashes will have moved from ninth to third in the world ranking of burden of disease, as measured in disability adjusted life years. The identification of effective strategies for the prevention of road traffic injuries is of global public health importance. Measures aimed at reducing traffic speed are considered essential to preventing road injuries; the use of speed enforcement detection devices (including speed cameras and radar and laser devices) is one such measure. ObjectivesTo assess whether the use of speed enforcement detection devices (SEDs) reduces the incidence of speeding, road traffic crashes, injuries and deaths. Search strategyWe searched the Cochrane Injuries Group's Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, other databases and reference lists of articles. We also contacted experts in the field. The searches were conducted during May to November 2004. Selection criteriaRandomised controlled trials and controlled before-after studies that assessed the impact of speed enforcement detection devices on speeding, road crashes, injuries and deaths were eligible for inclusion. Data collection and analysisWe independently screened search results, assessed studies for inclusion, extracted data and assessed methodological quality. Due to variability between and within included studies, a pooled analysis was not appropriate. Main resultsTwenty-six studies met the inclusion criteria. All but one study reported an absolute reduction in pre/post average speeds. A pre/post reduction in the proportion of speeding vehicles ranged across studies from 5% to 70% depending on the speed threshold set. Pre/post reductions of 50% to 65% were reported in the proportion of speeding vehicles travelling >15 km/h over the speed limit. Compared with controls, the relative improvement was from 1% to 15% for average speed and from 14% to 65% for percent speeding. All studies reporting crash outcomes reported an absolute pre/post reduction in all crashes and injury related crashes. In the vicinity of camera sites these pre/post reductions ranged from 14% to 72% for all crashes, 8% to 46% for injury crashes, and 40% to 45% for crashes resulting in fatalities or serious injuries. Compared with controls, the relative improvement in pre/post crash numbers resulting in any type of injury ranged from 5% to 36%. Authors' conclusionsDespite the methodological limitations of the studies reviewed, the consistency of reported positive reductions in speed and crash outcomes across all studies suggest that SEDs are a promising intervention for reducing the number of road traffic injuries and deaths. More studies of a scientifically rigorous nature are necessary to provide a stronger evidence base that these interventions are worthwhile. |