Speaks more to the (in)flexibility of Michigan drivers than it does any inherent safety risk with roundabouts. New roundabouts elsewhere have seen major drops in the number of crashes.
The safety statistics most often cited to the public are based on a 2000 study done by the Insurance Institute for Highway Safety. A few points should be considered. Of the 24 roundabouts analyzed, only 3 were previously signalized intersections (21 intersections were non-signalized). Also, no roundabout had an AADT of greater than 31,000 vehicles. The study observed that modern roundabouts have the following safety benefits:
- 38% reduction in total crashes
- 76% reduction in injury crashes
- 90% reduction in fatal and incapacitating-injury crashes
In 2011, the Wisconsin Department of Transportation funded a study that analyzed 24 roundabouts in their state. In the Wisconsin study, a roundabout with an AADT of 70,000 was analyzed (over twice the traffic volumes of any roundabout included in the 2000 study). Of the 24 roundabouts analyzed, 11 saw crashes increase after the roundabout was completed and 6 saw crashes increase by over 40%. Overall, they observed the following safety benefits:
- 9% reduction in total crashes
- 52% reduction in injury crashes
Here is a summary of the roundabouts analyzed in the Wisconsin study: