As an example, Peterson pointed to changes made along a section of Interstate 496 outside of Lansing, which accounted for 40 percent of reported incidents of aggressive driving in that area. When the speed limit was raised from 55 mph to 70 mph, incidents of aggressive driving dropped to zero.
“The low speed limit frustrated many drivers, so they drove over the speed limit. This caused problems for other drivers who were driving at the limit. The speed differential caused the tailgating, passing, and speeding that were reported as ‘aggressive’ driving,” Peterson said.
His data also showed accident rates in that area also fell when the speed limit was raised.
Surprisingly, the higher speed limit also improved traffic flow, nearly eliminating all symptoms of rush hour congestion along that stretch.