Traffic accidents are the leading cause of non-natural deaths worldwide. Lower speed limits may help prevent accidents. But speed-reduction policies can be controversial and effects are not well documented. A new study shows that speed reductions in Sao Paulo, Brazil, dramatically reduced fatal accidents and increased travel times only minimally.
A new study from University of Illinois shows that speed reductions in Sao Paulo, Brazil, dramatically reduced fatal accidents and increased travel times only minimally.
«We estimated that the social benefits of accident reductions greatly outweighed the social costs of increased travel time. Not only that, but it’s also a pro-poor policy that mainly benefits low-income residents,» says Peter Christensen, environmental economist in the U of I Department of Agricultural and Consumer Economics (ACE), and one of the study’s authors.
The city of Sao Paulo reduced speed limits on highways from 90 to 70 km/h in 2015. The controversial policy became a major focal point of the mayoral election in 2017, and the new mayor reversed the policy. This allowed the researchers to compare accidents at three points: before, during, and after the reduction in speed limits.
They found that over a period of 18 months, accidents decreased by 21.7% on roads affected by the policy. That equals approximately 1,889 averted accidents and 104 averted fatalities. Furthermore, they found that 86% of the benefits from reduced accident damages involved low-income residents; primarily pedestrians and motorcyclists.
«Our results indicate that speed limit reduction can be a very efficient life-saving policy,» Christensen points out. «In Sao Paulo, gun violence is the other major cause of unnatural death. It’s about the same magnitude as road accidents. Our study shows speed-reduction policies have a much bigger effect in terms of reducing fatalities than any policy we’re aware of to reduce violent crime,» he says.
Story Source: Materials provided by University of Illinois College of Agricultural, Consumer and Environmental Sciences. Original written by Marianne Stein. Note: Content may be edited for style and length.