What is Happening

State Route 37 (SR-37) sees an estimated 40,000 vehicles daily, making the 21-mile-trip between Vallejo and Novato one of the North Bay’s most traveled east/west highways. However, most of the road is projected to be submerged by sea level rise if modifications are not made to elevate the highway. Caltrans, alongside local and regional agencies as well as several environmental groups, has been working to improve the road’s resiliency for nearly a decade, but with frequent storm-related road closures due to flooding, the effects of sea level rise are indisputable. 

An area of great concern is the nine-mile stretch along the San Pablo Bay National Wildlife Refuge (NWR) from Sears Point to Mare Island, where traffic bottlenecks as the highway shrinks to a two-lane road. Caltrans is proposing an interim road-widening project that will enable car-pools, van-pools and eventually, express buses to relieve congestion. This project includes gray infrastructure such as sheet pile walls, and raising the road a few inches in areas that are low-lying. The Sierra Club is concerned this project does not address sea level rise in the long term, and does not advocate for equitable, mileage-based tolling. The project should focus on the resilience and the health of the Bay at the outset.

Why It Matters

The San Pablo Bay NRW is home to 20,000 acres of wetlands and vast ecosystems. Nestled right in the Pacific Flyway, it is an integral resting and feeding ground for migratory birds. The refuge is home to the west coast's largest wintering population of canvasbacks. San Pablo Bay provides critical habitat for endangered birds, mammals, and fish such as the salt marsh harvest mouse and California Ridgway's rail. 

Beyond clear ecological benefit, the health of the wetlands, the living shoreline of the Bay,  is necessary for combating climate change. Wetlands sequester carbon at a rate up to ten times higher than a tropical forest, and store up to 216 metric tons of carbon per acre. These resilient ecosystems are also our first and best line of defense against sea level rise. The soils and plant life work as an effective sponge for rising sea levels, and the habitat naturally migrates inland to adapt as levels rise. 

The nine-mile stretch of the highway between Mare Island and Sears Point currently acts as a levee, preventing natural tidal flows from reaching many existing and potential wetlands. 

The high-density of daily commuters on SR-37 is indicative of a larger equity problem. The 101 Highway corridor greatly lacks affordable housing, pushing significant portions of its workforce to settle in the comparatively more affordable Solano and Napa counties. The current state of SR-37 makes it an unreliable commute during seasonal storm surges as flooding leads to road closures. Tolls will be introduced to pay for future construction. Imposing this cost on commuters using single-occupant vehicles is inequitable. Currently there is no transit service, and funding for van-pools and eventual express bus service has not been established. 

Lastly, the interim project does not guarantee traffic improvements. City planners find that congestion initially decreases after lane-widening projects, but once word gets around of an improved commute, drivers switch their habits. This project could increase the amount of vehicles on the road and, subsequently, pollution in the air. 

Bay Alive Goals

• Advocate for the urgency of beginning construction on a causeway, rather than spending money on the interim lane-widening project. Sea level rise is an imminent, time-sensitive threat that requires immediate attention.
• Promote nature-based adaptations. The elevation of SR-37 would greatly increase connectivity between the Bay and existing wetlands, and improve Bay-wide resilience to climate change. 
• Increase public transportation in the area. There is currently no public transportation service on SR-37. A near-term improvement could be the implementation of an express bus while the long term goal of developing a rail line is met. The addition of a van-pool and eventual bus service, with diamond lanes will incentivize the reduction of single-passenger vehicles on the road.