Washington State DOT touts roundabouts

May 3, 2017 GMT

If you count the number of roundabouts then Washington is among the top three circle-happy states in the nation, after Wisconsin and Georgia.

That was one fact shared by a small delegation from the Washington state Department of Transportation that did a presentation about roundabouts at the Spokane Valley City Council meeting Tuesday evening.

Deputy Mayor Arne Woodard, who is no fan of roundabouts, was the one who invited WSDOT to do the session.

Brian Walsh, traffic design engineer for WSDOT, said the department has been building roundabouts since 1998 and that there are 120 on the state highway system.

“In any community, the first one is almost always the most difficult,” Walsh said.

Walsh said the WSDOT’s policy on roundabouts has been steadily evolving. “We certainly have been looking at this from the right perspective and we got quite a few down.”

Together with WSDOT traffic engineers Larry Frostad and Glenn Wagemann, Walsh put an emphasis on traffic safety.

“It used to always be speed, speed, speed,” Walsh said. “But we are now willing to trade off mainline speed for safety, and its worked out very well.”

Across the board, roundabouts have fewer crashes – or “conflicts” – than regular intersections, and the crashes that do happen are not as violent because speeds are slower in roundabouts.

Yet they can be a tough sell.

A recently constructed roundabout on State Route 243 in Mattawa in Western Grant County was not popular with locals.

Built at the intersection of Road 24 SW, locals were not convinced that it would slow down speeders at the same time as it allowed a large number of trucks through the area.

Walsh said WSDOT proposed the roundabout because there had been 21 collisions involving 43 vehicles in five years. The crashes resulted in two fatalities and 22 serious injuries.

Once the roundabout was built and drivers had gotten used to it, WSDOT received a letter from residents in Mattawa.

“They essentially apologized for saying that it wouldn’t work out,” Walsh said.

Wagemann talked about the proposed roundabouts in Deer Park which will be built in 2018.

“One intersection had 13 collisions one year. That is way too many,” he said.

He added that the Deer Park roundabouts also will slow down traffic, making any crashes much less severe.

Spokane Valley council members asked several questions about which traffic volume is appropriate for a roundabout.

Wagemann said a low volume would be under 5,000 cars a day and a high volume would be more than 30,000 cars a day.

“We have one in Gig Harbor and one in Tri-Cities that handle more than 30,000 cars a day,” Wagemann said.

There are no proposed roundabouts in Spokane Valley and Walsh made it very clear that it’s important to take the specific design of each intersection into consideration before deciding to build a roundabout.

Woodard thanked the WSDOT group for an informative presentation.

“I respond very well to data and statistics,” Woodard said.