The Effect of an Italian Nationwide Mandatory Visibility Aids Law for Cyclists

There is evidence that the conspicuity of cyclists is a contributory factor in some bicycle–motorized vehicle collisions and the use of visibility aids increases visibility and improves drivers’ responses in detection and recognition. To date, no study has evaluated the impact of a legislation imposing bicycling visibility aids on bicycle safety. The aim of the present study is to investigate whether a compulsory bicycling visibility aids law affects bicycle safety. Data on the monthly number of vehicles (including bicycles) involved in road accidents during the period 2001–2015 were obtained from the Italian National Institute of Statistics. Data were analyzed through an interrupted time-series analysis using an ordinary least-squares regression-based approach. Results revealed that the implementation of a legislation imposing bicycling visibility aids did not influence the number of bicycles involved in road accidents as well as its proportion in the total vehicles involved in road accidents. The introduction of the legislation did not produce immediate effects, nor did it have any effects over time.