F Llau Anthoni, Ahmed Nasar U, Khan Hafiz M R U, Cevallos Fabian G, Pekovic Vukosava
a Epidemiology, Robert Stempel School of Public Health, Florida International University , Miami , Florida.
b Biostatistics, Robert Stempel School of Public Health, Florida International University , Miami , Florida.
Traffic Inj Prev. 2015;16(8):773-80. doi: 10.1080/15389588.2015.1023896. Epub 2015 Mar 20.
To determine the safety effect of red light camera (RLC) programs, this study attempted to estimate its impact on collisions within Miami-Dade County, Florida Methods: A before-after evaluation using a comparison group along with traffic control correction was employed. Twenty signalized intersections with RLCs that began enforcement on January 1, 2011, were matched to 2 comparison sites located at least 2 miles from camera sites to minimize spillover effect. An empirical Bayes analysis was used to account for potential regression to the mean effects. An index of effectiveness along with 95% confidence intervals were calculated based on the comparison between the estimated and actual number of crashes in the after period.
During the first year, RLC sites experienced a marginal decrease in right angle/turn collisions (-3%), a significant increase in rear-end collisions (+40%), and significant decreases in all injury (-19%) and RLR-related injury collisions (-24%). An increase in right angle/turning (+14%) and rear-end (+51%) collisions at the RLC sites was observed after 2 years despite camera enforcement. A significant reduction in RLR-related injury crashes (-17%), however, was still observed after 2 years. A nonsignificant decline in all injury collisions (-12%) was also noted.
RLCs showed a benefit in reducing RLR-related injury collisions at camera sites after enforcement commenced, yet its tradeoff was a large increase in rear-end collisions. There was inconclusive evidence whether RLCs affected right angle/turning and all injury collisions. Statutory changes in crash reporting during the second year of camera enforcement affected the incidence of right angle and rear-end collisions; nevertheless, a "novelty effect" could not be ruled out. Future research should consider events such as low frequencies of severe injury/fatal collisions and changes in crash reporting requirements when conducting RLC analyses.
为确定红灯摄像头（RLC）项目的安全效果，本研究试图评估其对佛罗里达州迈阿密 - 戴德县内碰撞事故的影响。方法：采用前后评估法并设置对照组，同时进行交通控制校正。将20个于2011年1月1日开始启用RLC的信号控制交叉口，与距离摄像头位置至少2英里的2个对照地点进行匹配，以尽量减少溢出效应。采用经验贝叶斯分析来考虑潜在的均值回归效应。根据后期估计碰撞事故数量与实际碰撞事故数量的比较，计算有效性指数及95%置信区间。
在第一年，安装RLC的地点直角/转弯碰撞事故略有下降（-3%），追尾碰撞事故显著增加（+40%），所有伤害事故（-19%）和与RLR相关的伤害碰撞事故（-24%）显著减少。尽管有摄像头执法，但在2年后观察到安装RLC的地点直角/转弯碰撞事故（+14%）和追尾碰撞事故（+51%）有所增加。然而，2年后仍观察到与RLR相关的伤害碰撞事故显著减少（-17%）。还注意到所有伤害碰撞事故有不显著的下降（-12%）。
RLC在启用后对减少摄像头地点与RLR相关的伤害碰撞事故有好处，但其代价是追尾碰撞事故大幅增加。关于RLC是否影响直角/转弯碰撞事故和所有伤害碰撞事故，证据尚无定论。在摄像头执法的第二年，碰撞事故报告的法定变化影响了直角和追尾碰撞事故的发生率；然而，不能排除“新奇效应”。未来的研究在进行RLC分析时应考虑诸如严重伤害/致命碰撞事故发生率低以及碰撞事故报告要求变化等事件。
