Rapid growth of large cities throughout the world is having enormous impact on traffic safety in urban areas, according to a new study by researchers at the University of Michigan Transportation Research Institute (UMTRI). In particular, research indicates that high-density urban areas with 10 million or more people – dubbed megacities – are seeing higher fatality rates for pedestrians, bicyclists and motorcyclists.

"Recent reports have documented and discussed the ever-increasing urbanization of nations and the resulting increase in the number of megacities -- and the potential implications for traffic safety in these magacities," said UMTRI researcher Brandon Schoettle.

In a new study, Schoettle and colleague Michael Sivak examined road safety in two European megacities -- London and Paris. An earlier study by Sivak and colleague Shan Bao looked at New York and Los Angeles. In all four cities, fatal crashes involving drivers and passengers in vehicles are less prevalent relative to national rates for each country. However, for pedestrians, bicyclists and motorcyclists, fatality rates are much higher in the urban areas.

Researchers also found that megacities see a higher incidence of some specific types of crashes, such as single-vehicle and low-speed crashes. To read a U-M article summarizing the study's findings, click here.