Motorists on Highway 25 waiting on the light signal. Photo by Noe Magaña.
Motorists on Highway 25 waiting on the light signal. Photo by Noe Magaña.
Stage 1 of construction. Image courtesy of Caltrans.
Stage 1 of construction. Image courtesy of Caltrans.
Stage 2 of construction. Image courtesy of Caltrans.
Stage 2 of construction. Image courtesy of Caltrans.
Stage 3 of construction. Image courtesy of Caltrans.
Stage 3 of construction. Image courtesy of Caltrans.
Stage 4 of construction. Image courtesy of Caltrans.
Stage 4 of construction. Image courtesy of Caltrans.
Stage 5 of construction. Image courtesy of Caltrans.
Stage 5 of construction. Image courtesy of Caltrans.
Turbo roundabout example. Image courtesy of Caltrans.
Turbo roundabout example. Image courtesy of Caltrans.

Editor’s note: This article was last updated Feb. 22 at 2:15 p.m. to include additional information provided by Caltrans. 

Though construction of the turbo roundabout at the intersection of Highways 25 and 156 was scheduled to begin this month—according to project development reports previously submitted to the county—it’s been pushed back to April. 

The same reporting gave a construction cost estimate of $10.7 million. A revised estimate submitted at the Feb. 17. Council of San Benito Governments (COG) meeting put the cost at $13.7 million.

The project is funded through the State Highway Operation and Protection Program and is expected to be completed on April 2023.

Bidding for the project opened on Oct. 27, 2021 and was successfully awarded to Graniterock on Nov. 18 with a winning bid of $9.95 million. 

At the Feb. 17 COG meeting, Aaron Henkel, Caltrans project manager for the roundabout, presented the unique features of the project and the construction stages for building it.

According to Henkel, the roundabout design is innovative, but currently used in the Netherlands. It’s the first one in California using this design and only the second one in the U.S.

Each entrance to the roundabout comes off a two-lane road. Cars in the right lane have the option of turning right or continuing through a protected lane to cross the highway. Cars in the left lane enter a second protected lane which allows them to either continue to cross the highway or circle around for a left turn.

The design is intended to reduce the number of possible points of conflict between cars from 24, in a conventional roundabout, to 14, in the turbo roundabout. Signage leading up to the roundabout, about 350 feet away from the intersection, will help drivers unfamiliar with roundabouts to choose the correct lane.

Construction will be in five stages, with each stage reducing traffic to one lane in each direction. Temporary traffic signals will be installed to help regulate cars going through the construction area.

Caltrans told BenitoLink it does not estimate significant travel delays during construction. 

Henkel said the advantages of the turbo design include an emphasis on speed control, and giving drivers more time to slow down before entering and navigating the roundabout.

The presentation by Henkel was informational only. No vote was involved.

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