We empirically examine the relationship between traffic congestion and deaths in road accidents at the city level. We use panel data from 129 large cities in Europe for the period 2008-2017. We find strong evidence of a quadratic relationship between congestion and deaths in accidents, using both parametric and non-parametric econometric techniques. The threshold point at which the relationship between congestion and deaths in accidents is reversed and becomes positive occurs when congestion results in about a 30 per cent increase in travel time compared to a free flow situation. For most congested cities, any effective measure to contain congestion may also lead to better safety outcomes.

我们从经验上考察了城市一级道路交通事故中交通拥堵与​​死亡之间的关系。我们使用了2008年至2017年期间来自欧洲129个大城市的面板数据。我们发现，使用参数和非参数计量经济学技术，都可以发现交通拥堵与​​事故死亡之间呈二次关系的有力证据。与交通畅通相比，交通拥堵导致出行时间增加约30％，就会发生交通拥堵与​​事故死亡之间的关系逆转并变为正值的临界点。对于大多数拥挤的城市，任何有效的控制拥堵的措施也可能导致更好的安全结果。