December 12, 2012 - The cost of including the roundabouts is very similar to the cost of simply widening and reconstructing these intersections. Additionally, because the roundabouts actually increase the capacity of the road, they will allow us to construct the road with a narrower cross-section between the roundabouts, thus achieving the sake traffic capacity as a wider road with traditional signalized intersections. These narrower roadway cross sections are less expensive than the traditional wider cross sections would have been.
Additionally, the roundabouts offer significant safety enhancements when compared to signalized intersections (such as dramatically reduced likelihood of traffic fatalities and serious-injury accidents).
Therefore, we believe that including the roundabouts is, in fact, a very effective use of road funding.
I have also attached the Road Commission's "Top 10 Reasons to Like Roundabouts" document, which explains some of the reasons these have become very popular across the country.
1. 37% total reduction in crashes compared to signalized intersections.
2. 75% reduction in injury crashes compared to signalized intersections.
3. 90% reduction in traffic fatalities compared to signalized intersections.
4. Improved pedestrian safety compared to signalized intersections.
5. 30-50% increase in intersection traffic capacity with fewer delays.
6. Reduction of air pollution and fuel use due to fewer idling vehicles.
7. More visually appealing, with centerisland landscaping.
8. Long-term cost savings due to elimination of traffic-signal equipment.
9. Surveys show the majority of residents like roundabouts after having tried them.
10. Elimination of traditional left turns and the associated dangers.
Craig Bryson, APR
Public Information Officer
Road Commission for Oakland County