More cars on the road does not necessarily mean more crashes, according to researchers from the Michigan Department of Transportation and Michigan State University.
A recent study on 16 miles of Interstate in Detroit revealed that crash rates were very high at low levels of congestion, decreased rapidly as the number of vehicles increased, and rose again when congestion reached its peak.
The fact that overall crash rates were higher when congestion was lowest is attributed to the following factors: low traffic levels mean cars can go faster, single-car and rollover crashes are more common and lowest congestion levels usually occur late at night when drivers are more likely to be drowsy or have been drinking.
According to Christopher Johnson, research analyst at the AAA Foundation for Traffic Safety, drivers need to be aware that an empty road is not necessarily a safe one. “Just because there’s no traffic doesn’t mean that you can speed or decrease your attention,” he said.