文章基本信息

标题：Reducing Road Traffic Injuries: Effectiveness of Speed Cameras in an Urban Setting
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作者：Katherine Pérez ; Marc Marí-Dell’Olmo ; Aurelio Tobias 等
期刊名称：American journal of public health
印刷版ISSN：0090-0036
出版年度：2007
卷号：97
期号：9
页码：1632-1637
DOI：10.2105/AJPH.2006.093195
语种：English
出版社：American Public Health Association
摘要：Objectives. We assessed the effectiveness of speed cameras on Barcelona’s beltway in reducing the numbers of road collisions and injuries and the number of vehicles involved in collisions. Methods. We designed a time-series study with a comparison group to assess the effects of the speed cameras. The “intervention group” was the beltway, and the comparison group consisted of arterial roads on which no fixed speed cameras had been installed. The outcome measures were number of road collisions, number of people injured, and number of vehicles involved in collisions. We fit the data to Poisson regression models that were adjusted according to trends and seasonality. Results. The relative risk (RR) of a road collision occurring on the beltway after (vs before) installation of speed cameras was 0.73 (95% confidence interval [CI]=0.63, 0.85). This protective effect was greater during weekend periods. No differences were observed for arterial roads (RR=0.99; 95% CI=0.90, 1.10). Attributable fraction estimates for the 2 years of the study intervention showed 364 collisions prevented, 507 fewer people injured, and 789 fewer vehicles involved in collisions. Conclusions. Speed cameras installed in an urban setting are effective in reducing the numbers of road collisions and, consequently, the numbers of injured people and vehicles involved in collisions. Road traffic injuries are a major cause of mortality and morbidity worldwide. 1 There is evidence that driving speed is a risk factor for road collisions and for increased severity of road injuries. 2 The laws of physics support the view that, all else being equal, higher speeds will increase both the probability that an accident will occur and the severity of its consequences. 3 Therefore, interventions aiming to reduce speeds through engineering measures and law enforcement have been recommended and widely implemented. Speed cameras are one of the tools used in enforcing lower speeds. Although they have been widely used and many studies have been carried out to evaluate their effectiveness, evidence on their effects is still scarce. In their systematic review, Pilkington and Kinra reported that existing research consistently shows that introducing speed cameras is effective in reducing road traffic collisions and related casualties, but most studies have not included satisfactory comparison groups or suitably controlled for potential confounders. 4 Variables commonly regarded as having potential confounding effects on results of observational before-and-after studies of road safety measures 5 include regression to the mean, long-term trends in numbers of collisions or injuries (a systematic tendency for the number of accidents to rise or fall over a period of several years), 6 general changes in the number of collisions around the time when the road safety measure is introduced (i.e., differences between the periods before and after the measure is implemented), 6 changes in traffic volume, 3 and other specific interventions introduced around the same time as the road safety measure. A suitably designed study is necessary to address these factors, and that was our goal with the present investigation. We assessed the effectiveness of speed cameras installed on the beltway of Barcelona, Spain, in reducing numbers of road collisions, injuries, and vehicles involved in collisions. We also examined differences in effects between daytime and nighttime hours and between weekdays and weekends. Finally, we estimated numbers of collisions avoided and reductions in numbers of people injured and vehicles involved.