Traffic traverses the roundabout at North Boundary and Marshall roads in Cranberry Township shortly after it was opened in 2017. Butler Eagle file photo

The state Department of Transportation announced Monday that crashes decreased overall at 33 intersections replaced with roundabouts.

PennDOT compiled crash data using 33 roundabouts in 18 counties, including the ones in Cranberry and Clinton townships in Butler County, according to a PennDOT news release.

“We continue to see that Pennsylvania’s roundabouts save lives and reduce crash severity,” said Yassmin Gramian, PennDOT secretary. “While they aren’t the right option in every intersection, we’re pleased that they help to make our roadways safer.”

The 33 roundabouts studied are on state roads at intersections previously controlled by stop signs or signals.

The roundabouts chosen had at least three years of crash data available before they were built.

Department data showed:

• Suspected serious injuries were reduced by 76%

• Suspected minor injuries were reduced by 22%

• Possible and unknown severity injuries were reduced by 70%

• Total number of crashes decreased by 9%

The PennDOT study said while there was one fatality at a roundabout, there were three fatalities among the 33 locations before the roundabouts were built.

In addition to addressing unsafe intersections, roundabouts can also improve traffic flow, calm traffic and facilitate pedestrian mobility, according to PennDOT.

Lt. Chuck Mascellino of the Cranberry Township Police Department, said Tuesday the township’s ever-busier roads contain a total of five roundabouts.

Only one is on a state road — the roundabout on Glen Eden Road used in the PennDOT study.

Mascellino said the few crashes at the township’s roundabouts tend to be of the one-car variety.

He said many of the roundabouts are meant to keep traffic moving so drivers can more easily navigate the intersection.

“It does slow people down, so it does help with the speed issue as well,” Mascellino said.

He has not heard police officers complain about roundabouts slowing them down when they are hurrying to a call, which he thinks is due to the lack of a hard curb on the edges of the roundabouts.

“Our officers are trained in emergency driving,” Mascellino said.

He could not say which existing intersections should be replaced by roundabouts, as that is an engineering decision.

“They are kind of trending to be the preferred traffic control method throughout the state,” he said.

Instructional videos on how to navigate both single-lane and multi-lane roundabouts are on the PennDOT website, penndot.pa.gov, or on the PennDOT YouTube channel.