Novato Narrows on Highway 101 one of the Bay Area’s most congested, study finds

It's official. The stretch of Highway 101 from Novato to Petaluma is among the most congested freeway segments in the Bay Area, ranking among the top 50 for the first time since 2012, according to a new study.|

Does it feel like the notorious stretch of Highway 101 south of Petaluma known colloquially as the Novato Narrows has become an even tighter squeeze?

New data supports that perception.

The roughly 9-mile stretch from Atherton Avenue in Novato to East Washington Street in Petaluma ranked 40th on the list of the region’s 50 most congested freeway segments, compiled annually by the Metropolitan Transportation Commission.

The study found that motorists spent the equivalent of 880 hours in 2015 crawling along at speeds of 35 mph or less during peak commute hours northbound on the highway from 3 p.m. to 6:20 p.m.

It’s the first time since 2012 the segment has cracked the Top 50 rankings.

“It’s solid just about every workday,” CHP Officer Jon Sloat said.

No other stretch of Highway 101 through Sonoma County was ranked among the most congested freeways. For the first time in three years, the roughly 4½-mile stretch from Hopper to Baker avenues south of Highway 12 did not make the list.

But experts said that may reflect the fact that congestion generally has worsened elsewhere around the Bay Area, pushing some trouble spots down in the rankings.

The study reflects the highest recorded level of congestion delay on a per-commuter basis in the Bay Area, and a nearly 70 percent increase over the 1.9-minutes-per-commuter-per-day figure registered in 2010.

The most congested Bay Area freeway segment in 2015 was the 6-mile stretch out of San Francisco from Highway 101 to the Treasure Island portion of the Bay Bridge, which most days can take an hour to cover.

Second on the list was the westbound I-80 drive from Highway 4 in Hercules to Highway 101 in San Francisco. That segment earned the ignoble distinction of being the first in the Bay Area to have congestion uninterrupted by a midday break.

Congestion there typically extends from ?5:35 a.m. to 7:50 p.m.

Overall, the amount of time freeway traffic fell below 35 mph throughout the Bay Area increased ?22 percent over the previous year.

“Traffic all over the Bay Area is off the charts, with the worst of it being in the more urban centers,” said Suzanne Smith, executive director of the Sonoma County Transportation Authority.

Experts attribute the problem in part to the Bay Area’s booming economy and the distances people are forced to travel from work to areas of more affordable housing.

The region’s employment hit an all-time high of 3.7 million in 2015, with nearly half of the region’s jobs located in San Francisco or Silicon Valley.

The slow-down through the Novato Narrows also is exacerbated by a construction project that is raising and straightening the highway at the county line, near the crossing with San Antonio Creek. The creek often floods during heavy storms, sending water onto the highway.

The good news is that local transportation officials believe they have secured funding to complete carpool lanes on the 5-mile stretch of Highway 101 from the Petaluma River Bridge to just south of the county line.

The State Transportation Agency two weeks ago approved $15 million in funding for the widening project which, along with an additional $15 million from refunded bonds and another $1 million from a different earmark, will go toward the $37 million project.

But the goal of adding carpool lanes along the length of Highway 101 through Sonoma and Marin counties is still a pipe dream given current funding realities.

Plans to widen the highway in Sonoma County from Corona Road to the Petaluma River Bridge, a stretch of roughly ?3.5 miles, are on hold as officials seek to identify?$85 million needed to complete that project.

In Marin County, projects to widen about 6 miles of the highway heading south and 3 miles going north through the Narrows also are nowhere near completion. Those projects carry price tags of $120 million.

“I think in the Narrows, we have a good idea to fix it. We just don’t have the funding commitment to do the work,” said Randy Rentschler, an MTC spokesman.

You can reach Staff Writer Derek Moore at 707-521-5336 or

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