Construction begins on Rohnert Park roundabout

Construction has begun on Rohnert Park’s first roundabout and motorists should anticipate traffic delays into July.

It’s being installed at Commerce and Southwest boulevards, an intersection that’s directly east of Highway 101 and an entryway to a southern Rohnert Park commercial and residential area.

Commerce runs north and south and curves into Southwest as opposed to being a traditional T-intersection with straight roads.

Drivers are confined to narrow lanes on the east side of Commerce while work takes place on its western half. Homeowners say traffic is flowing smoothly outside of rush hour.

“That’s when tere’s a line of vehicles moving slow, yeah,” said Ronnie McDaniels, 70, who lives in the residential area northeast of the intersection. “I think people tried to get around by driving through my neighborhood, and that’s the issue right now.”

A roundabout is a road junction where traffic makes its way around a round island to reach a converging road. Drivers may need to yield to traffic but vehicles otherwise flow without having to stop.

The $1.9 million project includes replacement of a water line and rehabilitation of a sewer line.

Once completed, the roundabout should reduce traffic delays by a matter of seconds during mornings but more than a minute during the evening commute, according to Rohnert Park city staff.

Roundabouts generally reduce intersection fatalities by about 95%, said Kate Miller, executive director of the Napa Valley Transportation Authority.

They tend to be safer alternatives to traffic signals since the circular design forces vehicles to move at lower speeds that also allow bicyclists to safely traverse the road. The design also helps reduce certain types of collisions.

“There’s no opportunity for a T-bone,” Miller said. “The way an intersection works, you might get sideswiped or there might be a rear-end collision. But there is no potential for the type that causes major fatalities.“

Her agency partially funded a trio of roundabouts installed in Napa about two years ago and Miller said they have since improved traffic conditions in the area of Highway 29 and First Street.

“The roundabouts really slow cars down and that is really a benefit,“ Miller said.

In addition to safety, she added, roundabouts provide opportunities for landscaping and don’t require electrical maintenance that comes with traffic signals.

Installation depends heavily on whether an area can even fit the circular structure and the number of vehicle.

Acknowledging the trepidation among drivers entering roundabouts, Miller said “I think the learning curve drops dramatically the more you use it.“

You can reach Staff Writer Colin Atagi at colin.atagi@pressdemocrat.com. On Twitter @colin_atagi