Highway 37 threatened by rising sea level, alternate routes presented

A series of routes were presented Tuesday as potential alternatives to Highway 37 where rising sea levels threaten the 21-mile corridor running through Marin, Sonoma, Napa and Solano counties.

Caltrans is conducting a comprehensive study that may identify alternate routes and modes of transportation, like buses and light rails, for those traveling along San Pablo Bay where marshlands dot the landscape.

Routes cover 120 miles and would essentially link Highway 101 in Marin County to Interstate 80 in Solano County via existing highways and private roads, though options include a bridge parallel to Highway 37.

Tentative plans were presented during a public meeting and officials stressed none of the potential routes, or alignments, are set in stone.They encouraged attendees to provide feedback while all factors are taken into consideration for the long-term project.

“Obviously some of the modes won’t work on some of the alignments and we understand that,” Tammy Massengale, Caltrans District 4 coordinator, said during the meeting.

Officials emphasized that the study is in its early stages and they’re trying to find a solution to a problem that will present itself in the future.

Caltrans reported portions of Highway 37 could be “completely inundated” by 2050 with other flooding events happening before then.

Exact costs for each alignment haven’t been identified and officials reiterated to attendees that the study is being done to answer many of their questions.

One attendee asked about the number of lanes per each alignment and another inquired if studies were done about the weather.

A Vallejo resident, only identified as Robert, stressed toll plazas could have a negative impact on his neighbors.

“The threat of tolls on 37 would be crippling,” he said.

For now, multiple short-term projects are in the works for the highway where flooding and congestion are prevalent, especially during rush hour.

Efforts include the Sears Point to Mare Island Improvement Project, which covers a 10.4-mile stretch in Sonoma and Napa counties.

The project, which will be presented during a Feb. 2 meeting, looks at options to widen Highway 37 and relieve congestion.

Traffic in each direction is limited to one lane in the project area and officials are considering options like adding extra lanes, widening shoulders or turning the stretch into a three-lane road with a movable center median.

Under the latter option, a median can be shifted in either direction to create a second lane for the side of the road with heavier traffic.

You can reach Staff Writer Colin Atagi at colin.atagi@pressdemocrat.com. On Twitter @colin_atagi