Objectives: To determine factors affecting the severity of moped and motorcycle injuries in Barcelona--the city with the highest number of motorcycles per inhabitants in Europe--paying special attention to differences across vehicle type and to the role of congestion in a city that has promoted powered two-wheelers (PTWs) to alleviate traffic density.
Method: Drawing on Barcelona's local police census database on casualties (2002-2008), we use a parametric estimation based on an ordered multinomial logistic regression in order to identify factors affecting injury severity. We control for demographic characteristics, environment and traffic conditions, primary causes of accidents, and regulatory measures. Regressions distinguish PTW casualties from the rest of vehicles and present results for motorcycles and mopeds separately.
Results: We confirm the higher vulnerability of PTW casualties-especially motorcycle casualties (OR 2.30)-and show that factors such as gender, excess speed, road width, and alcohol consumption do affect casualty severity. Regarding traffic conditions, we find that congestion diminishes the probability of suffering severe injuries, although its statistical significance only appears for motorcycle casualties (odds ratio [OR] 0.80), which are also more severe due to speed violations (OR 6.29).
Conclusions: We confirm the negative relationship between traffic flow (congestion) and injury severity of PTWs casualties. This is clearly identified, at least for motorcycle casualties, although moped casualties present similar impacts as well. As a result, alleviating congestion through PTWs promotion turns out to be a trade-off between congestion and safety that public officers must consider. The article also highlights the need of awareness campaigns and safety policies focused on specific groups of drivers. Attention should also be given to the enforcement of speed limits and alcohol restrictions in Barcelona.