photo credit: Caltrans

Bumper to bumper, stop and go, could a roundabout cure your traffic woes?

That's the bet south of Sonoma, where Caltrans has rolled out a new roundabout at the consistently jammed-up intersection of Highways 121 and 116.

The familiar four-way stop in Big Bend where the two state routes meet is no more.

The gas station, hotel and other business haven't gone anywhere, but the stops signs have, and in their place: a roundabout.

"The reception for the roundabout has been positive, very positive," said Jeff Weiss. "In fact, we opened the roundabout partially in January of 2025...and motorist took right to it. It was almost like it had always been there."

Weiss is a spokesperson for Caltrans District 4, which covers Sonoma County and the Bay Area.

California's road transportation agency has been a proponent of roundabouts recently, since first opening the door to them in the 1990's.

The state's first "turbo roundabout" - similar to those found in the Netherlands - opened in early 2024 near Gilroy; and Caltrans is currently researching public attitudes to roundabouts across the state.

There's a long list of reasons for the roundabout favoring: they don't need the electrical infrastructure a stop light does, they reduce fatal and injury crashes by more than 75%, and Weiss said, the more constant traffic flow is a big plus.

photo credit: Noah Abrams/KRCB
The new roundabout at Highway 121 and Highway 116 in Big Bend south of the City of Sonoma.

"You talk to traffic engineers, sometimes people don't mind a detour as much as you think because at least they're moving," Weiss said. "When you put in one-way traffic control, they're stopped and that's frustrating. So, there's a psychology behind it, but the psychology is real."

Weiss said Sonoma County is a sort of roundabout sweet-spot: there's lots of 1-lane highways, and traffic counts are going up, making roundabouts an ideal way to slow drivers down at intersections, without stopping them completely.

While the new Big Bend roundabout hasn't been a perfect silver bullet for the intersections notorious back ups, it's still got plenty of cars on the roll.