Highway 101/25 interchange plans progress

Board approves report for first phase of project

An overhead image shows the conceptual plan for a new interchange at Highways 101 and 25 south of Gilroy. Graphic by Santa Clara Valley Transportation Authority

The Santa Clara Valley Transportation Authority Board of Directors approved a document June 2 that completes another step in the years-long process to construct a new overcrossing at the chronically congested Highway 101/25 interchange.

The board unanimously approved the addendum to an environmental report for a Highway 101 widening project that was previously OK’d in 2013. The addendum focuses on the first phase of the Highway 101/25 interchange, and determined that mitigation measures in place for the project would not add any new or significant environmental effects.

Located just south of Gilroy city limits, the current interchange, built in 1988, was originally meant to be a temporary way to prevent drivers from turning left on Highway 101 to Highway 25, Project Manager Karsten Adam said during a 2021 meeting on the project. However, the interchange has proven inadequate as the population has grown over the decades, and traffic on southbound Highway 101 backs up past Monterey Street during daily commute hours, as drivers attempting to navigate onto Highway 25 into San Benito County line up on the freeway’s shoulder.

While still being designed, the project would increase the length of the southbound Highway 101 offramp by more than 1,000 feet, according to Adam, with the goal of preventing vehicles from stacking on 101 during peak commute hours.

Traffic signals would be installed where the offramp meets Highway 25, and traffic would turn east over a newly constructed four-lane overpass that spans Highway 101.

Once crossing the overpass, which would be located slightly north of the current overcrossing, another signalized intersection will be constructed where the northbound off-ramp meets Highway 25.

The overall project, which also includes widening Highway 101 from Monterey Street in Gilroy to Highway 129 in San Benito County as well as extending Santa Teresa Boulevard to Highway 25, will be built in phases due to limited funding, Adam said, which is expected to cost at least $500 million in today’s dollars. 

The first phase, which includes the new overpass, is expected to cost $100 million, according to Adam, funded by Senate Bill 1 and the 2016 voter-approved Measure B.

Construction is tentatively planned to begin in mid-2024 and take three years to complete.

With the June 2 approval, the VTA will continue seeking right-of-way approvals on properties surrounding the project. That includes acquiring and demolishing the Garlic Shoppe and Rapazzini Winery, which are in the path of the proposed northbound Highway 101 off- and on-ramps, according to the VTA’s addendum.

The first phase of construction would also block off highway access on Castro Valley and Mesa roads, two popular merging points for commuters looking to bypass the congested Monterey Street onramp.

Adam said traffic would detour through Gilroy to the Monterey Street onramp until the Santa Teresa Boulevard extension to the new interchange is completed, which currently has no timeline.

Gilroy resident Robert Weaver wrote to the board, stating the traffic impact upon south Gilroy would be “immense.” Commuters would be diverted to the neighborhood thoroughfare of Thomas Road before crossing over the narrow two-lane bridge on Luchessa Avenue before heading onto Monterey Street.

“I am not challenging the necessity of this project, just how it is being executed,” he wrote, suggesting the Santa Teresa Boulevard extension be constructed first. “I see the collateral damage to our neighborhood as being unnecessarily prolonged.”

For information, visit vta.org/projects/us-101sr-25-interchange-phase-1.