By Age-Friendly Carbondale
This week, moving south along State Highway 133, we’ll examine the Main Street roundabout. Roundabouts are increasingly popular with the public and traffic engineers. They cost about as much to install as intersections with traffic lights, move traffic more efficiently and are touted by the U.S. Department of Transportation as reducing fatality and serious injury rates by as much as 82%. What’s not to like? We were surprised that on our comment cards, the roundabout was mentioned as problematic more often than any other intersection. Residents made comments like:
“Car coming downvalley did not slow down, did not see me in crosswalk and narrowly missed me. Now I am afraid to walk across at the roundabout.”
“Pickup truck did not stop. I was halfway across. Double-lane entrance creates frequent problems. Second car’s view of crosswalk and my view of that car obstructed by first car.”
Such comments appear to identify irresponsible drivers as the primary danger, but a basic tenet of modern road design is that vulnerable user safety cannot depend on self-managed driver behaviors. Driver behavior must be redundantly designed into the road itself.
Upon investigation, we found that conclusions about roundabout safety benefits are drawn mostly from studies of motorized vehicle accidents. Federal and state guidelines favoring roundabouts point to lower vehicle speeds, fewer pedestrian/bicycle–motorized vehicle conflict points and safer pedestrian starting locations to support assertions that roundabouts are safer for pedestrians and cyclists. This may be correct, but we were unable to find convincing empirical research testing that assertion. In fact, some experts disagree with it.
Moreover, much of the data we do have refers to single-lane roundabouts. Ours has two lanes. In their information guide on roundabouts, the Federal Highway Administration says, “Pedestrians crossing double-lane roundabouts are exposed for a longer time, and to faster vehicles. They can also be obscured from, or not see, approaching vehicles in adjacent lanes if vehicles in the nearest lane yield to them. Children, wheelchair users and visually-impaired pedestrians face particular risks. Bicycles are also more exposed to severe conflicts when choosing to circulate with motor vehicles.” Limited research indicates that two-lane roundabouts reduce serious accidents by as little as 9% and may even increase them.
CDOT operations engineer Bill Crawford confirmed that two lanes are more dangerous than one. Nonetheless, he said that CDOT believes roundabout safety at Main Street is acceptable, and that two lanes are needed to handle existing and anticipated volume. CDOT would oppose redesigning it to one lane.
In closing, we can only say that our roundabout is there, it’s staying, it probably ought to be made safer than it is and we have some ideas around doing that. Stay tuned and we’ll try to keep you in the loop, so to speak.