A new 'crisscross' interchange in Vallejo is expected to reduce peak-hour traffic by 90%
Interchange in Vallejo, Calif. on Highway 37 near Fairgrounds Drive.
VALLEJO, Calif. - A unique "crisscross" traffic configuration is coming to the North Bay as Caltrans and the Solano Transportation Authority prepare to open the Fairgrounds interchange on Highway 37 in Vallejo.
The innovative "crisscross" design will eliminate the need for two traffic lights, which officials expect to reduce peak-hour delays by more than 90%.
The interchange is slated to open May 16.
How much did the interchange project cost?
The backstory:
At a cost of $25 million, the project is significantly cheaper than a traditional cloverleaf and includes protected median paths for pedestrians and cyclists.
Known as a Diverging Diamond Interchange, the design shifts traffic to the opposite side of the road to allow for free left turns onto the highway without crossing oncoming lanes.
While the configuration may initially seem unconventional to drivers, officials say the efficiency gains are substantial.
"The traffic is gonna crisscross at an intersection. There's no crisscrossing of traffic at the same time," said John Adams, the Solano County interchange site engineer and manager.
Nick Burton, projects director for the Solano Transportation Authority, noted that by allowing drivers to enter westbound Highway 37 from the left side of the road, the design eliminates the need for two separate traffic lights.
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How the Highway 37 interchange will improve peak-hour traffic
This change is expected to slash peak-hour congestion from 600 minutes of delay to just 30 minutes — a reduction of over 90%.
The $25 million project is also a cost-effective alternative to traditional designs.
A standard cloverleaf interchange would cost an estimated $100 million.
Improving safety for pedestrians and cyclists
Dig deeper:
Beyond savings, the new layout addresses safety concerns regarding traffic backing up onto the main lanes of Highway 37.
Vallejo Mayor Andrea Sorce highlighted the benefits for the local community and visitors to Six Flags Discovery Kingdom.
"I'm excited about is it's gonna make that experience safer whether they're in their car, on bikes or on feet," Sorce said.
Pedestrians and cyclists will also be able to travel through the interchange via a protected median separated from vehicle traffic by barriers.
This interchange marks the first of its kind in the Bay Area, following a similar installation in Manteca.
Caltrans spokesman Bart Ney indicated the agency is looking at implementing this design at various other locations across the state.
The project also serves as the initial phase of a broader effort to elevate and widen Highway 37 from Vallejo to Highway 101 in Marin County.
The Source: Caltrans, Solano Transportation Authority, Vallejo Mayor Andrea Sorce, Solano County's interchange site engineer and manager.