Funding approved for Highway 37 traffic, flooding study

The nine-month effort will identify segments of roadway to fix, but the construction work is still unfunded.|

A group of agencies exploring solutions to flooding and traffic on Highway 37 has taken its first significant step, funding a study that is anticipated to identify actual projects that can be built along the 21-mile roadway. But with construction funds lacking, officials are unsure when any of the future work might take place.

The Sonoma County Transportation Authority on Monday chipped in $30,000, the final piece of funding for the Highway 37 feasibility study. Other transportation agencies in Marin, Napa and Solano counties paid similar amounts while the Metropolitan Transportation Commission funded the bulk of the $1 million study by contractors Kimley Horn and AECOM.

Supervisor David Rabbitt, who chairs a committee of officials from the four counties that Highway 37 passes through on its route from Highway 101 to Highway 80, said the study is expected to provide a blueprint that will allow officials to prioritize segments of the roadway construction.

“We all recognize that Highway 37 is a vital east-west link,” he said. “We need to make sure it’s going to be there in the future.”

The highway, which skirts the edge of San Pablo Bay, is subject to sea level rise and flooding. The segment east of Sonoma Raceway narrows to two lanes and is prone to traffic bottlenecks. Rabbitt said that, so far, solutions have ranged from abandoning the roadway to the rising tide, to building a seawall to building an elevated causeway and charging a toll.

The toll idea has been proposed by United Bridge Partners, a private firm that has build toll roads and bridges in other parts of the country. Under that proposal, the state would relinquish the right of way to the company, which would fund the construction and charge a toll to recoup its cost.

Rabbitt said some sort of public-private partnership may be the solution to constructing the roadway. At current funding levels, Caltrans, which operates Highway 37, would not be able to complete the work until 2088, Rabbitt said. A UC Davis study estimated that the complete project would cost $1 to $4 billion.

Complicating the effort, Highway 37 has long been looked at as secondary to other primary routes in the North Bay. In Sonoma and Marin counties, widening of Highway 101 takes precedent for limited transportation dollars, Rabbitt said.

“In each county, it’s our second priority,” he said. “That make it difficult.”

The feasibility study is expected to be completed by around the end of the year and will look at the impacts of sea level rise and traffic alleviation, including drainage and shoreline improvements, levee improvements and raising the roadway, said James Cameron, director of projects and planning at the SCTA.

“At the end of the study, we should have a document with enough detail to allow the policy committee to identify projects to move forward into the environmental phase,” he said.

While sea level rise will likely begin to inundate Highway 37 within 30 years, parts of the roadway have already been impacted by flooding this winter during high tides and storm surges. Last month, the western portion of the route in Marin County was closed for two weeks as crews worked around the clock to repair the damage.

As part of the work, crews installed larger, 36-inch pipes under the roadway to help with drainage. Other work included installing a barrier of sheet piling into the ground as well as concrete bulwark along the eastbound lanes, which had shifted in the storms. The works cost an estimated $8 million, Rabbitt said.

“We’re very happy Caltrans took emergency action to fix the low-lying area that flooded on the Marin side,” he said.

(Contact Matt Brown at

UPDATED: Please read and follow our commenting policy:

  • This is a family newspaper, please use a kind and respectful tone.
  • No profanity, hate speech or personal attacks. No off-topic remarks.
  • No disinformation about current events.
  • We will remove any comments — or commenters — that do not follow this commenting policy.