Drivers in the North Bay waited 30 years for a new lane to alleviate congestion on Highway 101. But now some wish the project had never finished.

That’s because it came with new carpool hours, meant to align Marin and Sonoma counties with the rest of the Bay Area. Regional transportation officials have tried to standardize the window for high-occupancy vehicles - with at least one passenger in addition to the driver - to two weekday rush hour periods. The morning period runs from 5 a.m. to 10 a.m., while the evening starts at 3 p.m. and ends at 7 p.m.

Officials at Caltrans imposed this split-schedule after adding diamond lanes to fix a notorious bottleneck between Petaluma and Novato, while also filling a “gap” in the 52-mile carpool lane network on 101, from Windsor to Mill Valley. Notably, the new hours apply to all 52 miles, which means one infrastructure project has vastly expanded the carpool window in both counties.

For some, the change feels seismic.

Suddenly, motorists who found themselves jammed up on 101 would peer out their windows at a tantalizing sight: a beautiful and woefully-underused diamond lane. With transit and carpools thinning out after 9 a.m., some drivers observed, with intensifying bitterness, that the diamond lane appeared to be sitting empty.

People balked. They panned the new carpool hour regime as a “one size fits all” solution. They criticized officials for spending years on a project aimed to ease traffic, only to defeat the purpose entirely. They objected so loudly that leaders in Marin and Sonoma County are now lobbying Caltrans to reverse course.

“This is an unmitigated disaster,” said Eric Grover, who drives each morning from his home in Novato to an office in San Francisco’s Upper Market neighborhood.

Before the carpool hours took effect in September, Grover typically left his house at 6:45 a.m., and slid into his desk at 7:30 a.m. Now he starts driving at 6:30 a.m. and straggles into work at 7:45 a.m., having endured an extra 25 minutes of waiting in gridlock.

Aerial views of the new lane construction along U.S. Route 101 freeway near Petaluma, in August. The widening of the road took decades to finish, but now some commuters say it’s made traffic worse during rush hour periods. (Richard H. Grant/S.F. Chronicle)

Another Novato resident, Carol Meyers, said her commute to San Rafael has swelled from 20 minutes to upwards of an hour.

“All that to travel 12 miles,” she said.

It’s the latest chapter for a monumental freeway project that was supposed to revolutionize mobility in the Bay Area, partly by adding that third lane at the infamous Marin-Sonoma Narrows, but also by imposing rules to prioritize buses and ride shares. Although the rebuild dated to an era when planners embraced road-widening as a solution for congestion, it also reflected a more forward-thinking idea about multi-modal corridors.

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Yet as it neared the finish line, the 101 overhaul became a source of drama and division. Many people who expected to glide down the freeway found they were hitting more snarls and moving slower. More than a few blamed Caltrans’ emphasis on high-occupancy transport, which had so far done little to nudge people out of their cars.

“You wait so long through all this construction,” said Nikki Gelardi, a Novato resident who drives to work in Santa Rosa. “And then none of it makes sense.”

Granted, others applauded Caltrans and other transportation agencies for the tough love approach.

“This is an opportunity for a real do-over, one that prioritizes smarter travel choices rather than sliding back into old habits,” a woman from Santa Rosa wrote, in an email to the Metropolitan Transportation Commission, which helped advise Caltrans on the carpool hours.

“Strong HOV rules are not about punishing commuters - they’re about building a healthier, more efficient transportation system for all of us,” the email concluded.

Debate about carpool hours stewed for months as Caltrans crews finished widening the Narrows between Novato and the county line. Crews broadened that 6-mile section from two lanes to three, an expensive and complicated project that came with conditions. Chiefly, the state permit required that third lane to be reserved for carpools at least part time, and environmental documents called for consistent hours between the counties.

Such requirements provoked bickering. Traditionally, Marin carpool hours ran from 6:30 to 8:30 a.m., only in the southbound direction, during morning rush hour. In the evenings, Marin’s carpool restrictions started at 4:30 p.m. and ended at 7 p.m. Sonoma, by contrast, had carpool hours from 7 to 9 a.m. and 3 to 6:30 p.m. in both directions.

Nobody quite knew where the twain should meet. Officials at Caltrans decided to compromise by spreading - or, perhaps, exacerbating - the misery, extending what had been about 5 hours of carpool a day in both counties to a new normal of 9 hours.

The new schedule, which is the same heading north as heading south, went live a few weeks before the third lane opened on the Narrows. This was, by all measures, a fraught moment. Owners of electric vehicles were on the verge of losing their carpool lane privilege on Oct. 1 (with enforcement to start in December), a development that would likely push solo drivers into the general-purpose lanes. School had started, which increased traffic.

If multiple factors contribute to the snarls on 101, a lot of commuters cite a plainly visible explanation: sparse carpool lanes next to general lanes that are bumper-to-bumper. Grover said he became grateful for the solo drivers who snuck into the carpool lane and created a little more balance.

“If it wasn’t for the cheaters, it could be worse,” he said.

It didn’t take long for the backlash to coalesce. John Goodwin, an MTC spokesperson, said he has already received scores of phone calls and emails with complaints - and a couple expressing support. He has tried to address everyone’s concerns and explain the rationale.

“Adding a third lane meant the third lane was required to be a carpool lane,” he said. “It stands to reason that the operating hours for the carpool lane be consistent throughout the corridor,” he added, referring to the full 52 miles. Moreover, Goodwin noted, other Bay Area freeways hew to these carpool hours.

An online petition protesting the hours had nearly 8,000 signatures as of Friday.

Under mounting pressure, the transportation authorities in Marin and Sonoma County sent a joint letter to Caltrans, asking officials for a “shorter” carpool duration, potentially 6 to 9 a.m. and 3 to 6:30 p.m., and not wait six months or longer to consider changes.

Staff at Caltrans assured in a statement that they are working “as quickly as possible” to gather data, understand the impacts of the revised HOV hours, and “determine the best path forward.”

“Caltrans and MTC are monitoring traffic data, including speeds in the HOV lanes and general-purpose lanes, vehicle occupancy counts, as well as the duration and length of congestion,” the statement read. It referenced a new data dashboard that Caltrans and other transportation agencies are making, to provide up-to-date traffic analysis.

Carter Lavin, a climate activist in Oakland, was disappointed to see this abrupt retreat. He views the longer HOV hours on 101 as an opportunity for culture change in North Bay suburbs where people love to drive.

“Our government spent huge amounts of taxpayer dollars on an asset that people in these communities have been clamoring for, even though widening freeways is a climate catastrophe,” Lavin said. He hoped that by prioritizing carpools, Marin and Sonoma transportation authorities could compensate for some of the damage.

“It should be easy for the counties to collaborate with Caltrans to advertise the carpool lane,” Lavin said. “There’s a lot of social media, there are so many ways to get the word out.”

Perhaps, Lavin suggested, transportation leaders could try something adventurous: a Tinder-style app that could match drivers with potential riders.

Gelardi said she has carpooled in the past and abstractly likes the concept, but that it’s become more difficult in an era of remote work.

“A lot of jobs will let you leave at 3 p.m. and finish the day at home, but it’s hard to do that if you have to wait for your ride,”

Anne Richman, executive director of the Transportation Authority of Marin, remains committed to the urban-planning philosophy behind the 101 project. She and her colleagues “want to be supportive of transit and carpooling,” while underscoring the positive impact of the third lane, which has relieved chokepoints, Richman said. Nonetheless, she acknowledged that slowdowns now seem to be occurring on other parts of 101, including the portion south of the Narrows, from Novato to San Rafael.

Whether the beefed-up carpool hours are entirely to blame is unclear. One alternative theory is that the Narrows effectively metered the flow of cars during peak hours. Now it’s a bit like an unclogged pipe, releasing more traffic southward.

Novato drivers like Grover and Meyers don’t begrudge their neighbors to the north for wanting some relief. They believe 101 could improve everywhere if carpool hours were limited to times when people are more likely to carpool.

Grover echoed Richman’s sentiments, assuring that he’s generally “all in for the carpool lane.” Just not at the expense of a project that took 30 years to build.

This article originally published at New stretch of California Highway 101 finally opened. Drivers say it’s led to ‘unmitigated disaster’.