Institute of Transport Economics, Gaustadalleen 21, NO-0349 Oslo, Norway.
Accid Anal Prev. 2013 Oct;59:394-8. doi: 10.1016/j.aap.2013.06.039. Epub 2013 Jul 6.
Studies that have evaluated the effects on accidents of daytime running lights for cars have consistently found that cars using daytime running lights are involved in fewer multi-party accidents in daylight than cars not using daytime running lights. However, studies evaluating the effects of mandatory use of daytime running lights have not always found an accident reduction. Although findings are mixed, there is a tendency for the aggregate effects of daytime running lights (i.e. the effects of an increasing share of traffic using daytime running lights) to be smaller than the intrinsic effects (i.e. the difference in accident involvement between cars using and not using daytime running lights). This paper presents a game-theoretic model to explain these apparently inconsistent findings. The game-theoretic model is based on so called Schelling-diagrams, originally introduced by Nobel laureate in economics Schelling. The effects of daytime running lights are modelled by means of Schelling-diagrams. It is shown that it is by no means impossible for cars using daytime running lights to always be safer than cars not using daytime running lights, while the total number of accidents remains constant even if the percentage of cars using daytime running lights increases from, say, 10% to 90%.
研究表明，日间行车灯可减少汽车日间事故的发生，装有日间行车灯的汽车比没有装日间行车灯的汽车在日间发生多方事故的概率更低。然而，评估日间行车灯强制使用效果的研究并不总是能发现事故减少。虽然结果不一，但日间行车灯的总体效果（即使用日间行车灯的交通比例增加的效果）往往小于固有效果（即使用和不使用日间行车灯的汽车之间的事故发生率差异）。本文提出了一个博弈论模型来解释这些明显不一致的发现。博弈论模型基于所谓的谢林点图（Schelling diagrams），由诺贝尔经济学奖得主谢林（Schelling）首次提出。谢林点图被用来模拟日间行车灯的效果。结果表明，装有日间行车灯的汽车总是比没有装日间行车灯的汽车更安全，而即使装有日间行车灯的汽车比例从 10%增加到 90%，事故总数也保持不变，这并非不可能。
