Safety, traffic flow, and a first for the U.S.

From the Federal Highway Administration

Replacing a traditional intersection with a roundabout can reduce the number of crashes by 35 percent. Even more impressive: roundabouts bring the number of fatalities down by 90 percent!

At SCJ, we’ve been doing roundabouts for a long time. Senior Principal Perry Shea designed Washington’s first state route roundabout in 1998. Since then, our team has completed various stages of analysis, design, and construction for more than 50 roundabout intersections in Washington, Oregon, and Alaska.

Currently, Principal Scott Sawyer and his team are working on a series of three roundabouts in a high-traffic area of Tumwater. Here, it’s not just about safety, it’s also about traffic flow.

“Roundabouts perform better than a signal in keeping vehicles moving, especially during off-peak hours,” Scott said. “When it isn’t rush hour, the roundabout is always moving, as opposed to having to randomly wait at a red light.”

Earlier this year, we welcomed national roundabout expert, Brad Shea, to the team.

“Brad’s breadth of experience and depth of knowledge about roundabouts is second to none,” said SCJ Principal Amy Head. “He’s led projects across the country, into Canada and in our own backyard.”

Right now, Brad is working on the City of Aberdeen’s first roundabout and multiple roundabouts in Thurston County. Additionally, more far flung, is a project for Valley Metro in Arizona, where we’re evaluating incorporating light-rail through the middle of a roundabout – a first for the United States.

To learn more about SCJ’s roundabout work, check out some of our previous projects.


  1. Mr. Vick, perhaps it is the fact that you wanted a re-vote so that VC Rd. would be maintained as a two lane road instead of a four lane road that makes people learn of your ideas. Yes, people drive too fast now, but the roundabouts won”t stop that. The roundabouts will only slow them at the roundabout itself and until the drivers can accelerate to the speed they want to drive. The speed AND the volume of traffic is the problem as I see it. Good luck with the roundabouts.

    1. You are correct. Roundabouts will only slow vehicles at the intersections where the majority of conflicts occur, and will not control speed between intersections. Roundabout approach geometry is designed to encourage vehicles to reduce their speed prior to arriving at the roundabout where conflicts with pedestrians and other vehicles are more likely to occur. As you have mentioned, roundabout design is definitely a balance of capacity, speed and safety.

  2. thank you so much for the new chapter.


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