No Roundabout Way

The benefits of roundabouts have been laid out for decades, but it seems the news hasn’t made its way around. Here is an overview of the safety, congestion, sustainability, and reservations surrounding roundabouts.

Roundabouts increase safety for both vehicles and pedestrians. The drastically reduced conflict points eliminate crossing lane turns and head-on collision opportunities. This enables new and elderly drivers to operate vehicles at intersections attentively.

“Studies of intersections in the United States converted from traffic signals or stop signs to roundabouts have found reductions in injury crashes of 72-80 percent and reductions in all crashes of 35-47 percent, in addition to a 90% decrease in fatalities” (1,4)

The shape requires decreased speed for navigation and the central median promotes focus by blocking oncoming traffic, especially with headlights at night. When it comes to pedestrians, there is only one direction of traffic to avoid crossing into the median. Walking around the intersection decreases the number of cars crossed and enables clearer crosswalk right-of-way.

With a 30-50% increase in capacity, there is a huge opportunity for congestion relief. Implementation decreases delays up to 89% (4). Congestion relief decreases noise and surrounding community impacts, while contributing to improved quality of life for road users and stakeholders alike.

“Roundabouts decrease stops by up to 56%”

Less idling of vehicles, more opportunity for median green space, less need for incoming lanes to increase capacity, the impacts of decreasing emissions seem clear. Roundabout congestion reduction alone could decrease fuel emissions by 23-24% (1)

Something less popular today, there are challenges in implementation. There is a learning curve when it comes to circles and many existing intersections do not have the surrounding space needs to be converted to roundabouts. Median space maintenance is another consideration. Roundabouts can be difficult to integrate into existing complex light networks.

Sometimes complex to navigate with very large vehicles, this can be addressed by traversable aprons that can be driven over by trucks for a few feet if necessary, eliminating straight-faced curbs.

States like New York and Virginia have “roundabout first” policies, requiring the preferred consideration of roundabouts. FDOT highlights the financial savings, noting the elimination of signal costs, no need for power or outage coverage, while safe and usable transportation promotes support of local businesses.

Would you put roundabouts first? Would you want your community to?

 Sources

https://www.iihs.org/topics/roundabouts#:~:text=Roundabouts%20are%20a%20safer%20alternative,are%20better%20for%20the%20environment.(1) https://highways.dot.gov/safety/proven-safety-countermeasures/roundabouts (2) https://nap.nationalacademies.org/download/27069# (3) https://www.fdot.gov/agencyresources/roundabouts/benefits.shtm (4) https://wsdot.wa.gov/travel/traffic-safety-methods/roundabouts (5) https://www.asce.org/publications-and-news/civil-engineering-source/civil-engineering-magazine/issues/magazine-issue/article/2021/03/modern-roundabouts-boost-traffic-safety-and-efficiency (6)