Center for Evaluation of Value and Risk in Health (CEVR), Tufts Medical Center, Boston, Massachusetts, USA.
Mailman School of Public Health, Columbia University, New York City, New York, USA.
Inj Prev. 2018 Aug;24(4):262-266. doi: 10.1136/injuryprev-2017-042340. Epub 2017 Aug 16.
Vehicle speed changes impact the probability of injuring a pedestrian in ways that differ from the way that it impacts the probability of a collision or of death. Therefore, return on investment in speed reduction programmes has complex and unpredictable manifests. The objective of this study is to analyse the impact of motor vehicle speed reduction on the collision-related morbidity and mortality rates of urban pedestrians.
We created a simple way to estimate the public health impacts of traffic speed changes using a Markov model. Our outcome measures include the cost of injury, quality-adjusted life years (QALYs) gained and probability of death and injury due to a road traffic collision. Our two-way sensitivity analysis of speed, both before the implementation of a speed reduction programme and after, shows that, due to key differences in the probability of injury compared with the probability of death, speed reduction programmes may decrease the probability of death while leaving the probability of injury unchanged. The net result of this difference may lead to an increase in injury costs due to the implementation of a speed reduction programme. We find that even small investments in speed reductions have the potential to produce gains in QALYs.
Our reported costs, effects and incremental cost-effectiveness ratios may assist urban governments and stakeholders to rethink the value of local traffic calming programmes and to implement speed limits that would shift the trade-off to become between minor injuries and no injuries, rather than severe injuries and fatalities.
车辆速度的变化以不同于影响碰撞或死亡概率的方式影响伤害行人的概率。因此，减速计划的投资回报具有复杂且不可预测的表现。本研究的目的是分析机动车减速对城市行人与碰撞相关的发病率和死亡率的影响。
我们创建了一种使用马尔可夫模型估算交通速度变化对公共卫生影响的简单方法。我们的结果衡量指标包括伤害成本、获得的质量调整生命年（QALY）以及因道路交通碰撞而死亡和受伤的概率。我们对速度进行了双向敏感性分析，包括在实施减速计划之前和之后的速度，结果表明，由于与死亡概率相比受伤概率的关键差异，减速计划可能会降低死亡概率，同时保持受伤概率不变。这种差异的净结果可能会导致因实施减速计划而导致伤害成本增加。我们发现，即使是对减速的少量投资也有可能在 QALY 方面产生收益。
我们报告的成本、效果和增量成本效益比可能有助于城市政府和利益相关者重新思考当地交通平静化计划的价值，并实施限速，以将权衡从严重伤害和死亡转变为轻微伤害和无伤害。
