European countries have implemented the use of roundabouts for traffic safety for several years. Now, the city of Cedar Rapids, Iowa, is following suit, having turned to roundabouts to improve public safety and traffic operations.
“There are several reasons that go into why roundabouts are used. Traffic flow, safety and cost-benefit analysis are taken into consideration along with the environment and location of the area,” Cedar Rapids senior traffic engineer Ron Griffith said.
The city website — cedar-rapids.org — reports that roundabouts reduce fatalities by more than 90%, while also seeing a 35% reduction in crashes. The traffic structure also eliminates head-on crashes and right-angle crashes, among other things. The site adds roundabouts can improve traffic flow, especially during peak driving hours.
“Studies have shown that roundabouts help to reduce the need for all cars to stop at an intersection, which has also been shown to have a positive effect on air quality,” Griffith said. “Reduced speeds, fewer conflict points and the right-only approach to entering the roundabout all contribute to improved safety.”
“Traffic flow has improved and the severity of crashes has decreased,” Assistant Director for Public Works Brenna Fall said. “Roundabouts also improve pedestrian comfort and safety, as many are designed so that a person only needs to cross one lane of traffic at a time.”
According to the Iowa Department of Transportation, there are approximately 60 roundabout intersections across the state. Eleven of these roundabouts have been constructed in Cedar Rapids, a project that started in 2017. The city now plans to add nine more in the next two years, bringing the total of roundabouts to 20.
According to Griffith, the city has received traffic safety grants for several roundabout projects from the Iowa Department of Transportation. Capital Improvement Project funds are then used to supplement the safety funding, Griffith said.
Though roundabouts have been a common use in European countries, they are not common in the United States. According to Fall, the concept of roundabouts is still fairly new in Iowa and a lot of drivers reported they are uncomfortable with how a roundabout is supposed to operate.
“During project development, the city hosts public meetings, where renderings, brochures and videos are shared, and residents can ask questions about how roundabouts work,” Fall said.
When constructing these roundabouts, the city follows guidance provided by NCHRP Report 672 “Roundabouts: An Informational Guide, Second Edition” published by the Federal Highway Administration, Griffith stated.
According to Fall, the city’s experience has been mostly positive surrounding roundabouts, although it has taken time and effort to implement the first roundabout projects.
“Several years ago, there was not much support from elected officials, and the first roundabout projects proposed were not immediately approved,” Fall said. “As other communities in the area began to build them, the city continued to propose roundabouts for specific intersections where the most benefit could be realized.”
Fall stated the city has seen the most success at locations where traffic could be removed, an all-way stop condition could be avoided and near elementary and intermediate schools. Fall attributes the city’s outreach and education to the success of the roundabouts.
“When implementing a roundabout near a school, the outreach is especially focused on parents, bus drivers and school faculty and staff,” Fall said.
According to Fall, Cedar Rapids has provided the renderings, videos and other information on how to use roundabouts via the city’s website. These make education more easily accessible for drivers who are unaware of exactly how a roundabout works.
“In addition to public meetings, the city conducts traffic studies to determine if a roundabout would be the best solution for the designated area,” Fall said.
Fall said, when it comes to implementing roundabouts into traffic flow, start with single-lane ones, as they are easier to understand and maneuver. “Take the time to help educate drivers on how to safely drive in a roundabout to allow them to get more acclimated to the change,” Fall said.