Swedish National Road and Transport Research Institute, Olaus Magnus Road 35, SE - 58195 Linköping, Sweden.
Accid Anal Prev. 2018 May;114:34-39. doi: 10.1016/j.aap.2017.02.003. Epub 2017 Feb 20.
The effects of speed, both positive and negative, make speed a primary target for policy action. Driving speeds affect the risk of being involved in a crash and the injury severity as well as the noise and exhaust emissions. Starting 2008, the Swedish Transport Administration performed a review of the speed limits on the national rural road network. This review resulted in major changes of the speed limits on the rural road network. It was predominantly roads with a low traffic safety standard and unsatisfactory road sides that were selected for reduced speed limits, as well as roads with a good traffic safety record being selected for an increase in speed limits. During 2008 and 2009, speed limit changed on approximately 20,500km of roads, out of which approximately 2700km were assigned an increase, and 17,800km were assigned a reduction in speed limits. The aim of this study is predominantly to describe and analyse the longterm traffic safety effect of increased, as well as, reduced speed limits, but also to analyse the changes in actual driving speeds due to the changed speed limits. Traffic safety effects are investigated by means of a before and after study with control group and the effects on actual mean speeds are measured by a sampling survey in which speed was measured at randomly selected sites before and after the speed limit changes. Results show a reduction in fatalities on rural roads with reduced speed limit from 90 to 80km/h where the number of fatalities decreased by 14 per year, while no significant changes were seen for the seriously injured. On motorways with an increased speed limit to 120km/h, the number of seriously injured increased by about 15 per year, but no significant changes were seen for the number of deaths. The number of seriously injured increased on all types of motorways, but the worst development was seen for narrow motorways (21.5m wide). For 2+1 roads (a continuous three-lane cross-section with alternating passing lanes and the two directions of travel separated by a median barrier) with decreased speed limit from 110 to 100km/h, the seriously injured decreased by about 16 per year. As regards the change of mean speeds, a decrease in speed limit with 10km/h led to a decrease of mean speeds of around 2-3km/h and an increase of the speed limit with 10km/h resulted in an increase of mean speed by 3km/h. In conclusion, the results show that in total about 17 lives per year have been saved on the road network with changed speed limits. For comparison, 397 road users were killed in total during 2008. The number of seriously injured remain in principle unchanged. It should also be noted that the results are obtained for the road network which changed the speed limits during 2008 and 2009, and it is not certain that the results can be generalised to another road network.
速度的影响无论是正面的还是负面的，都使速度成为政策行动的主要目标。行驶速度会影响发生碰撞的风险以及受伤的严重程度，还会影响噪音和废气排放。自 2008 年以来，瑞典交通管理局对国家农村道路网的限速进行了审查。这次审查导致农村道路网的限速发生了重大变化。主要是选择交通安全标准较低且道路两侧条件较差的道路降低限速，同时选择交通安全记录良好的道路提高限速。在 2008 年和 2009 年期间，约有 20500 公里的道路限速发生了变化，其中约 2700 公里的限速提高，17800 公里的限速降低。本研究的主要目的是描述和分析提高和降低限速的长期交通安全效果，同时分析由于限速变化导致的实际行车速度的变化。通过采用对照组的前后研究来调查交通安全效果，并通过在限速变化前后在随机选择的地点进行抽样调查来测量实际平均速度的变化。结果表明，在限速从 90 公里/小时降低到 80 公里/小时的农村道路上，死亡率降低了 14 人/年，而重伤人数没有明显变化。在限速提高到 120 公里/小时的高速公路上，重伤人数每年增加约 15 人，但死亡人数没有明显变化。所有类型的高速公路上的重伤人数都有所增加，但最严重的情况出现在狭窄的高速公路（21.5 米宽）上。对于限速从 110 公里/小时降低到 100 公里/小时的 2+1 道路（一个连续的三车道横断面，设有交替的超车车道，两个行车方向由中央隔离带隔开），重伤人数每年减少约 16 人。至于平均速度的变化，限速降低 10 公里/小时会导致平均速度降低约 2-3 公里/小时，而限速提高 10 公里/小时会导致平均速度提高 3 公里/小时。总之，结果表明，在限速变化的道路网络上，每年总共约有 17 人因车祸丧生。相比之下，2008 年共有 397 名道路使用者死亡。重伤人数原则上保持不变。还应注意的是，这些结果是针对 2008 年和 2009 年限速变化的道路网络得出的，不能确定这些结果可以推广到另一个道路网络。
