A rare and endangered species could threaten the entire proposed Highway 156 widening project unless legislation is passed to deal with the issue, according to Transportation Agency for Monterey County officials.

Project manager Rich Deal told The Herald on Friday that the state Department of Fish and Wildlife has identified habitat for the Santa Cruz long-toed salamander along the route of the proposed new four-lane highway, as well as the new Castroville Boulevard interchange project that serves as the initial phase of the three-segment highway widening proposal.

Deal said Caltrans is pursuing a legislative fix in the spring that would allow development of alternative habitat for the salamander, which is a subspecies of the long-toed salamander and has been found only close to a few isolated ponds in Monterey and Santa Cruz counties. Caltrans has recommended a biological study to identify the extent of the salamander habitat along the proposed highway route, which Deal said is expected to take about two years to complete.

If the proposed legislation were to fail, Deal said the project would “basically be stopped.”

Now estimated to cost about $412 million, the highway widening project calls for a new four-lane highway to be built parallel and south of the existing two-lane roadway for about $106.2 million, as well as constructing a new Castroville Boulevard interchange to the east of the existing interchange for about $55.2 million, and installing a new interchange at Highway 101 for about $250.8 million.

For now, though, only the Castroville Boulevard interchange project is moving forward, bolstered by $30 million in voter-approved Measure X funding, because the other two segments lack a funding source.

The interchange project would include replacing the only stoplight along the highway with an overpass and three roundabouts, including one on either side of the overpass for vehicles exiting and entering the highway, and one at the intersection of the old and new Castroville Boulevard near the Monte Del Lago neighborhood. It would also include widening the highway to four lanes from the current interchange to the new one.

Deal said the interchange would function independently and be compatible with both the current highway configuration and the proposed four-lane highway.

The current interchange is considered the county’s top collision site along one of its most heavily traveled and congested roadways, which links the Monterey Peninsula and the Bay Area.

Currently, the interchange project is scheduled to begin construction in October 2022 and be completed by July 2024.

According to a staff report on the interchange project set for review by the Transportation Agency for Monterey County board last week but postponed to the board’s Jan. 22 meeting, the project is positioning itself to apply for $20 million in state SB 1 gas tax funding by preparing a hybrid multi-modal corridor plan to be considered by the board in March.

Eventually, the county is expected to extend Castroville Boulevard from the new interchange to Blackie Road in an effort to allow commercial trucks to avoid Castroville.

While TAMC has explored using a toll road concept to help pay for the proposed four-lane highway segment of the widening project, agency executive director Debbie Hale pointed out that it would still need about $75 million or more in state funding before it could move forward and the state is not currently expressing much interest in added lanes.