By Age-Friendly Carbondale

This week, heading south on State Highway 133, we’ll take a look at the Main Street Roundabout. Roundabouts are becoming increasingly popular with the public and traffic engineers. They cost about the same to install as signalized intersections, move traffic more efficiently, and are touted by the U.S. Department of Transportation as reducing fatalities and serious injuries by as much as 82 percent. What’s not to like? We were surprised to find that the roundabout was cited as problematic more often on our comment cards than any other intersection. Residents made comments such as:

“The car coming down the valley didn’t slow down, didn’t see me on the zebra crossing and narrowly missed me. Now I’m afraid to cross at the roundabout.”

“Pick-up truck didn’t stop. I was halfway. Double lanes often cause problems. The second car’s view of the zebra crossing and my view of that car was blocked by the first car.”

Such comments seem to identify irresponsible drivers as the primary danger, but a basic principle of modern road design is that the safety of vulnerable users cannot depend on self-directed driver behavior. Driver behavior must be designed redundantly into the road itself.

Upon investigation, we found that conclusions about the benefits of roundabout safety are drawn primarily from studies of motor vehicle crashes. Federal and state guidelines favoring roundabouts point to lower vehicle speeds, fewer conflict points between pedestrians/bicycles and motor vehicles, and safer pedestrian starting locations to support claims that roundabouts are safer for pedestrians and bicyclists. This may be true, but we could not find any compelling empirical research testing this claim. In fact, some experts disagree.

Additionally, much of the data we have is for single-lane roundabouts. Ours has two. In their roundabout information guide, the Federal Highway Administration says, “Pedestrians crossing two-lane roundabouts are exposed to faster vehicles for longer. They may also be blocked by or not see approaching vehicles in adjacent lanes if vehicles in the nearest lane yield to them. Children, wheelchair users, and visually impaired pedestrians are at particular risk. Cyclists are also more exposed to serious conflicts when they choose to ride with motor vehicles.” Limited research indicates that two-lane roundabouts reduce serious crashes by only 9% and may actually increase them.

CDOT operations engineer Bill Crawford confirmed that two lanes are more dangerous than one. However, he said CDOT believes the safety of the Main Street roundabout is acceptable and that two lanes are needed to handle existing and projected traffic volumes. CDOT would oppose a one-lane redesign.

In conclusion, all we can say is that our roundabout is here, it’s here to stay, it probably needs to be made safer than it is, and we have some ideas on how to do that. Stay tuned and we’ll try to keep you updated, so to speak.