Do advanced stop lines for motorcycles improve road safety

Abstract Background In Barcelona, Advanced Stop Lines (ASL) for motorcycles, were implemented since 2009. This paper aims to assess the effectiveness of ASL for motorcycles in preventing road traffic collisions. Methods A quasi-experimental design of an evaluation study of an intervention with comparison group was performed. 35 ASL were implemented in 2009 (phase I) and 16 in 2010 (phase II). The study areas were: ASL area and 30 m preceding (34 m); Crosswalk and intersection (CROSS). For each ASL, a nearby comparison zone was chosen. Data on crashes were provided by police and included geocodes. Outcome variables were the number of injury collisions, people injured, collisions involving motorcycles, and of motorcycle drivers involved. Relative risks (RR) and their 95% confidence intervals, in the post-intervention period with respect to the pre-intervention, were estimated using Poisson-lognormal regression models, with a random area factor. The models were adjusted for traffic volume and street characteristics. Results In Phase I, the annual mean of people injured were 50 pre- and 63 post-intervention in the ASL-34m area, and 234 and 197 in the ASL-CROSS area. After adjustment, in the ASL-34m, significant increases were found in the risk of collision (RR = 1.34 [1.12–1.61]), being injured (RR = 1.26 [1.01–1.58]), motorcycle involvement (RR = 1.44 [1.17–1.78]), and being a motorcycle driver involved (RR = 1.39 [1.10–1.75]). In the comparison zones (34 m), only the risk of being injured increased (RR = 1.42 [1.09–1.85]). In the ASL-CROSS area, there were no significant changes in risk, but in the comparison zones (CROSS) decreases were found in the risk of being injured (RR = 0.86 [0.75–0.98]) and of being a motorcycle driver involved (RR = 0.85 [0.74–0.98]). In phase II, there were no significant changes in risks. Conclusion ASL are not effective in improving road safety. In some circumstances, they increase the risk of traffic injury.