Richter Elihu D, Friedman Lee S, Berman Tamar, Rivkind Avraham
Hebrew University-Hadassah School of Community Medicine and Public Health, Injury Prevention Center, Jerusalem, Israel.
Am J Prev Med. 2005 Dec;29(5):440-9. doi: 10.1016/j.amepre.2005.08.035.
To determine why road deaths dropped by 33.9% in the United Kingdom, compared to 6.5% in the United States, between 1990 and 1999.
Deaths per billion vehicle kilometers traveled (D/BVKM), and case fatality rates (CFR) in the United States and the United Kingdom were tracked. Time trends in CFR can be used to track the direct effects of speed of impact. CFR is a crash-phase outcome that is independent of exposure, and varies approximately to the fourth power of the speed of crash impact. Joinpoint regression analysis was used to analyze changes in time trends of CFR.
In the 1990s, the decrease in deaths in the United Kingdom was attributable mostly to the 29.6% drop in the CFR. In the United States, the CFR dropped by only 6.6%. The United Kingdom introduced speed cameras and an array of speed-calming measures. By contrast, in the United States, use of speed cameras was extremely rare, and speed limits and speeds increased in 32 of the 50 states, mostly in 1995 and 1996, after which CFR actually rose (p<.0001). Intercountry differences in time trends in seat belt use, trauma care, vehicle kilometers traveled, congestion, and driving under the influence of alcohol (DUI), along with massive increase in use of higher-risk sports utility vehicles in the United States, did not account for the contrasting trends in deaths through the 1990s. But increases in DUI in the United States after 1997 may have contributed to increases in speed-related crashes.
The reductions in CFR, probably from small drops in speed of impact account for the disproportionately greater drop in death tolls in the United Kingdom compared to the United States. The temporal fit between drops in CFR and deaths following the introduction of speed cameras in the United Kingdom and increases in speed (speed creep), CFR, and deaths in the United States following raised speed limits suggests that diverging changes in speeds of impact accounted mainly for these changes. Use of D/BVKM to correct for exposure concealed the lack of progress after 1990 in the United States, since falling time trends in D/BVKM reflect increases in congestion. If the United States had implemented United Kingdom-type speed control policies and not raised speed limits, there would have been an estimated 6500 to 10,000 (approximately 16% to 25%) fewer road deaths per year during the period following speed-limit increases (1996 to 1999), including many DUI-related deaths. Reductions of up to 50% are now achievable based on newer population-wide strategies for speed control.
确定为何在1990年至1999年期间，英国道路死亡人数下降了33.9%，而美国仅下降了6.5%。
追踪美国和英国每十亿车公里行驶里程的死亡人数（D/BVKM）以及病死率（CFR）。CFR的时间趋势可用于追踪碰撞速度的直接影响。CFR是一个与暴露无关的碰撞阶段结果，并且大约随碰撞速度的四次方变化。采用连接点回归分析来分析CFR时间趋势的变化。
在20世纪90年代，英国死亡人数的减少主要归因于病死率下降了29.6%。在美国，病死率仅下降了6.6%。英国引入了测速摄像头以及一系列减速措施。相比之下，在美国，测速摄像头的使用极为罕见，并且在50个州中的32个州，速度限制和车速都有所提高，大多是在1995年和1996年，此后病死率实际上有所上升（p<0.0001）。在安全带使用、创伤护理、车公里行驶里程、拥堵以及酒后驾车（DUI）方面的时间趋势的国家间差异，以及美国高风险运动型多用途汽车使用的大幅增加，并不能解释20世纪90年代死亡人数的对比趋势。但是1997年之后美国DUI的增加可能导致了与速度相关的撞车事故增加。
病死率的降低，可能源于碰撞速度的小幅下降，这解释了与美国相比，英国死亡人数下降幅度不成比例地更大的原因。英国引入测速摄像头后病死率下降与死亡人数下降之间的时间契合度，以及美国提高速度限制后速度（速度攀升）、病死率和死亡人数的增加表明，碰撞速度的不同变化主要解释了这些变化。使用D/BVKM来校正暴露掩盖了美国1990年后缺乏进展的情况，因为D/BVKM时间趋势的下降反映了拥堵的增加。如果美国实施英国式的速度控制政策而不是提高速度限制，那么在速度限制增加后的时期（1996年至1999年），估计每年道路死亡人数将减少6500至10000人（约16%至25%），包括许多与DUI相关的死亡。基于更新的全人群速度控制策略，现在可实现高达50%的降幅。
