Hu Wen, Cicchino Jessica B
Insurance Institute for Highway Safety, Arlington, Virginia, USA
Insurance Institute for Highway Safety, Arlington, Virginia, USA.
Inj Prev. 2020 Apr;26(2):99-102. doi: 10.1136/injuryprev-2018-043025. Epub 2019 Jan 13.
Effective 9 January 2017, the default speed limit on Boston streets was reduced from 30 mph to 25 mph. This study evaluated the effects of the speed limit reduction on speeds in Boston.
Vehicle speeds were collected at sites in Boston where the speed limit was lowered, and at control sites in Providence, Rhode Island, where the speed limit remained unchanged, before and after the speed limit change in Boston. A log-linear regression model estimated the change in vehicle speeds associated with the speed limit reduction. Separate logistic regression models estimated changes in the odds of vehicles exceeding 25 mph, 30 mph and 35 mph associated with the lower speed limit.
The speed limit reduction was associated with a 0.3 % reduction in mean speeds (p=0.065), and reductions of 2.9%, 8.5% and 29.3 % in the odds of vehicles exceeding 25 mph, 30 mph and 35 mph, respectively. All these reductions were statistically significant.
Local communities should consider lowering speed limits to reduce speeds and improve safety for all road users. The current practice of setting speed limits according to the 85th percentile free-flow speeds, without consideration of other characteristics of the roadway, can be a hurdle for local communities looking to lower speed limits. Updated state laws that allow municipalities to set lower speed limits on urban streets without requiring costly engineering studies can provide flexibility to municipalities to set speed limits that are safe for all road users.
自2017年1月9日起，波士顿街道的默认限速从每小时30英里降至每小时25英里。本研究评估了限速降低对波士顿车速的影响。
在波士顿限速降低的地点以及罗德岛州普罗维登斯的对照地点（限速保持不变），于波士顿限速改变前后收集车速数据。对数线性回归模型估计了与限速降低相关的车速变化。单独的逻辑回归模型估计了与较低限速相关的车辆超过每小时25英里、30英里和35英里的几率变化。
限速降低与平均车速降低0.3%相关（p = 0.065），车辆超过每小时25英里、30英里和35英里的几率分别降低2.9%、8.5%和29.3%。所有这些降低均具有统计学意义。
当地社区应考虑降低限速，以降低车速并提高所有道路使用者的安全性。当前根据第85百分位自由流车速设定限速而不考虑道路其他特征的做法，可能会成为当地社区降低限速的障碍。更新后的州法律允许市政当局在不要求进行成本高昂的工程研究的情况下降低城市街道的限速，可为市政当局提供灵活性，以设定对所有道路使用者都安全的限速。
