Roundabouts continue to grow in popularity across Pennsylvania
While some drivers in Butler County may have strong negative opinions about roundabouts, others are unlikely to think twice about venturing through a roundabout during their daily commutes.
But the traffic control measure — designed to slow motorists down to roughly 25 mph or less — is proving to be one of the safest and most efficient ways to move cars through busy intersections, according to a recent study by the state Department of Transportation.
A 2024 PennDOT study of 47 roundabouts on state-maintained routes found that crashes resulting in injuries dropped by 51% and total crashes fell 7% after construction of a roundabout. The study used 20 years of crash data from roundabouts around the state.
National studies have also found changing two-way sign-controlled intersections to a single-lane roundabout have reduced injury crashes by more than 80%.
Few places in Butler County have embraced them more than Cranberry Township.
For Ron Henshaw, Cranberry Township’s director of planning and development services, enhanced safety is an advantage.
“What I’ve learned — and this has been reinforced by communities out in Indiana that are really big on roundabouts — is that the number of fatal accidents is drastically reduced,” he said. “The speeds are so much lower that when accidents do happen, they’re typically fender benders.
“People walk away from them.”
Roundabouts aren’t installed without major planning efforts, Henshaw said. Each project begins with an in-depth evaluation, one that Henshaw says mirrors PennDOT’s own process for traffic signals.
“Roundabouts are traffic control features, just like signals,” he said. “And before anything gets built, it has to be proven to be needed — we call that being ‘warranted.’ PennDOT does a great job of setting those standards so things are consistent across Pennsylvania.”
Once the township determines that a roundabout could fit, planners examine a range of other factors — from property ownership and topography to nearby streams and utility lines.
“If the terrain is too steep or the environmental impacts are too high, sometimes it’s just not feasible,” Henshaw said. “We start with the idea of a roundabout, but if it can’t work, we move on to other traffic control options.”
While roundabouts aren’t necessarily cheaper to build — Henshaw said they often require more land than a signalized intersection — they tend to save money over time.
“We call it legacy cost,” he said. “That’s what it costs to maintain a traffic feature year after year.”
With roundabouts, there’s no electronics, sensors and signal systems that need regular maintenance.
“So even if they’re not less expensive upfront, they’re definitely more cost-effective over the long run,” he said.
Tips from PennDOT on navigating roundabouts
- Slow down and be prepared to yield to pedestrians in the crosswalk.
- Circulating traffic has the right of way. Look left and check for approaching traffic. If there are multiple circulating lanes, yield to both before entering. Do not assume the vehicle in the inside lane will stay there.
- Do not stop while in the circulatory roadway and always use your right turn signal to indicate your exit.
Of course, the circular design brings its own challenges, especially when winter hits Western Pennsylvania.
“Roundabouts can be tricky for snowplow operators,” Henshaw admitted. “They’ve got to maneuver carefully without damaging curbs or crosswalks.
“But our public works team has really mastered it. They plan their snow routes, learn where they can and can’t go — and at this point, it’s pretty seamless.”
With one new roundabout planned for the intersection of Unionville and Glen Eden roads, Cranberry Township shows no signs of slowing down on its commitment to safer, smarter infrastructure.
For Henshaw, the reasoning behind that approach is simple. “It comes down to two things,” he said. “Safety — that’s always number one — and smart long-term planning for our residents. Roundabouts help us achieve both.”
