After 14 years of construction, and many more years of planning, the new carpool lanes on Highway 101 between Marin County and Sonoma County opened Monday.
“There is still work on the project, but the three-lane configuration is complete,” said Matt O’Donnell, a spokesperson for Caltrans.
The $762 million Marin-Sonoma Narrows widening project added a third lane north and south on the 16-mile stretch between Novato and Petaluma. The corridor received its “Novato Narrows” nickname because the road contracted to two lanes in each direction, creating daily traffic jams.
Now there is a contiguous stretch of carpool lanes for about 50 miles, from the Richardson Bay Bridge in Marin to Windsor in Sonoma County.
“Decades in the making and many millions of dollars later, we can finally retire the ‘narrows’ moniker in Marin and Sonoma,” said Marin County Supervisor Eric Lucan, the chair of the Transportation Authority of Marin board. “This huge milestone exemplifies our ability to compete for funds and deliver big projects that will have a tangible daily impact in the lives of every resident.”
Anne Richman, executive director of the Transportation Authority of Marin, one of the partners on the project, said it’s a big moment.
“We realize it’s taken a lot of persistence and patience and teamwork to get here, and there is still some work out on the corridor being completed,” Richman said. “But we are very pleased to have reached this milestone.”
The project was broken into 13 construction phases. The current phase, known as B7, will continue for another two months or so.
“We still have more other paving, final striping, signing, drainage kind of work left after this milestone,” O’Donnell said. “Construction should be expected to continue into about November, but we anticipate that traffic delays will be minimal as most of the work is scheduled at night.”
There will be overnight closures on northbound Highway 101 this week from 8 p.m. to 7 a.m. to accommodate the construction. San Antonio Road on- and off-ramps are scheduled to be closed at the same time.
Traffic advisories will be issued as the construction progresses.
While this completes work on the highway, there are some smaller related projects that still need to be completed. The projects include utility relocation and restoration of the San Antonio Creek Bridge, and widening San Antonio Road to add class 2 bike lanes.
Richman said there isn’t a timeline for those projects yet.
The widening will also prompt ongoing mitigation and monitoring for at least another 10 years.
The opening of the commuter lanes comes as drivers are adjusting to and complaining about new carpool hours in the two counties. The new carpool hours are from 5 to 10 a.m. and 3 to 7 p.m. on weekdays in both directions.
Before that, hours had been less restrictive: 7 to 9 a.m. and 3 to 6 p.m. in both directions in Sonoma County. HOV lane hours in Marin had been 6:30 to 8:30 a.m. southbound, and 4:30 to 7 p.m. going north.
Caltrans imposed the expanded hours to make the carpool restrictions consistent in both counties and to align with the hours on the state-owned bridges.
Officials at the Transportation Authority of Marin sent a letter to Caltrans in April voicing concerns. The letter stated that a recent analysis shows the new restrictions “would introduce additional local auto and transit impacts, by increasing queue length and duration of congestion” during the morning commute in San Rafael and in the afternoon commute in Corte Madera.
At the time, Lucan said none of the state-owned bridges are contiguous with this section of Highway 101, so he couldn’t see why the hours needed to align.
“In addition to navigating my way through the congestion myself trying to get my kids to school, I also continue to hear from residents almost daily,” Lucan said on Monday. “Through the Transportation Authority of Marin, we expressed our concerns to Caltrans about the expanded hours before the decision was made, after it was made, and I continue to communicate the ongoing concerns.”
Mill Valley resident Peter Sorensen, who commutes to Novato three or four days a week, said there has been a noticeable change in driving patterns since the new restrictions took effect.
“You start to see bottlenecks, you start to see people race around people; more people are changing lanes; more stop-and-go driving,” Sorensen said.
Sorensen said his understanding of the HOV lane is that it is intended to encourage solo drivers to take transit or to carpool, and in turn it is supposed to reduce traffic for everyone.
“If you can’t measure the effect to see if you’re actually reducing traffic for the betterment of all us, then it’s wrong to have an HOV lane,” he said. “You should be able to state a purpose and demonstrate that your purpose is being fulfilled. I want something that works. This doesn’t work.”
Richman said TAM has been receiving messages from concerned residents.
“We understand that this is an adjustment, and we would just like to give it some time to stabilize,” Richman said. “There are a lot of changes in the corridor happening over a short period of time.”
Officials will continue to monitor traffic after all improvements have been completed and will make adjustments, as needed, once traffic normalizes to avoid over correction, O’Donnell said.
