Roundabout project. Photo courtesy of Caltrans District 5.

Information provided by Caltrans District 5

Editor’s note: This press release was updated with more recent information about the construction start date. Previous version stated construction was scheduled to begin April 18.

Caltrans District 5 announced the construction of the roundabout at the intersection of Highways 25 and 156 is scheduled to begin May 9.

The contractor for this $10.7 million construction project is Graniterock of San Jose and the project is scheduled to be completed in April 2023.

According to the release, the roundabout is designed to advance safety and is intended to reduce the number and severity of collisions at the intersection of Highways 25 and 156 where the current signalized intersection is experiencing a pattern of broadside and rear end collisions due to a recurrence of red light runs.

During a 2019 meeting with county residents former Caltrans project manager Brandy Rider said there were 126 collisions between 2009 and 2018, almost double the state average for similar intersections. Two fatalities resulted from those collisions.

The release also said that once construction begins, speed limits throughout the construction zone will be reduced to 35 mph. The speed limits will apply to all four approaches to the intersection of the two highways and is necessary to provide for the safety of travelers and construction crews.

Caltrans said the intersection will continue to be signalized during all phases of construction. During the first several months of construction work will take place adjacent to the intersection. Message and directional signs will be in place to assist travelers.

Caltrans advises commuters to allow extra time for your commute through the area.

The agency also said that roundabouts that have been installed in California to replace existing signalized intersections have proven to be effective solutions to safety and capacity issues.

To address safety concerns Caltrans has implemented several small projects since 2011 that modified the existing signal at this intersection. These included adjusting the signal timing, installing “signal ahead” signs, installing flashing beacons, and upgrading the size of the signal heads.

“Although these countermeasures have had some benefit, the replacement of the signalized intersection with a roundabout will achieve the overarching safety benefit of reducing the frequency and severity of collisions at this location,” Caltrans said.

The roundabout is funded by the Caltrans State Highway Operation and Protection Program, which funds safety projects.

An interchange at Highways 25 and 156 intersection is the long-range improvement planned as part of the larger Highway 25 Expressway Conversion Project. The Measure G-funded project to widen Highway 25 (to be completed over the coming years) will also include a permanent interchange at this intersection.

“In the interim, Caltrans is addressing this safety need until the long-range plan for an interchange can be implemented,” the release said.

Caltrans said the roundabout design would emphasize speed control and its design features would control the speed that vehicles enter, navigate, and exit the roundabout.

“Lower vehicle speeds provide more time for entering drivers to judge, adjust speed for, and enter a gap in circulating traffic, allowing for safer merges while reducing the frequency and severity of collisions,” the release said.

It added that the roundabout is a two-lane design and anticipates truck volumes for the intersection today and into the future. In accommodating the sweep of truck trailer wheels, a mountable truck apron is featured around the inside of the roundabout.