At the end of 2005, Autostrade per l’Italia (ASPI) and the Italian traffic police progressively deployed along the Italian tolled motorway network an average speed enforcement system, named Safety Tutor, able to determine the average speed of vehicles over a long section to encourage drivers to comply with speed limits and improve safety. The aim of this study was to empirically test the extent to which Safety Tutor led to a reduction in both total and fatal accidents on Italian highways during the period of 2001–2017. To do so, we carried out a generalized difference-in-differences estimation using a unique panel dataset that exploits the heterogeneous accident data within all tolled motorway sectors in a quasi-experimental setting. To deal with the potential endogeneity of the non-random placement of Safety Tutor sites, we utilized an instrumental variable strategy by using the network of motorway sectors managed by ASPI and its controlled concessionaires from 2005 onwards (i.e., when the technology was available) as an instrument to predict Safety Tutor adoption. We found that a 10% increase in Safety Tutor coverage led to an average reduction in total accidents of 3.9%, whereas there is no evidence of a significant causal effect of Safety Tutor in reducing fatal accidents.

2005年底，意大利汽车贸易协会（ASPI）和意大利交通警察在意大利收费高速公路网络上逐步部署了名为“安全导师”的平均速度执行系统，该系统可以确定车辆在较长时间内的平均速度，以鼓励驾驶员遵守限速并提高安全性。这项研究的目的是对2001年至2017年期间，安全导师导致意大利高速公路上的总事故和致命事故减少的程度进行经验测试。为此，我们使用唯一的面板数据集进行了一般差异差异估计，该面板数据集在准实验环境中利用了所有收费高速公路扇区内的异构事故数据。为了应对安全家教网站非随机放置的潜在内生性，从2005年起（即当该技术可用时），ASPI及其受控制的特许经营者作为预测安全教员采用率的工具。我们发现，安全导师的覆盖率提高10％导致事故总数平均减少3.9％，而没有证据表明安全导师在减少致命事故方面具有显着的因果作用。