CA: A 'world without BART': Major outages show how bad Bay Area traffic can get

Ask any Bay Area resident to pick their worst commute of last year, and they might choose between two unexpectedly disastrous Friday mornings.

There was May 9, when a computer glitch forced the system to shut down for hours. An uncannily similar network outage halted trains on Sept. 5, giving the impression that BART is a transit system in constant triage.

Without train service during rush hour, harried office workers pulled out their phones to summon ride-hails or arrange carpools with friends. Some got into their own cars. Freeways that are usually calm on Fridays were suddenly snarled with traffic.

Now, officials at Metropolitan Transportation Commission have provided the most granular picture to date of how the two meltdowns impacted key roads and arteries, particularly for those traveling from East Bay suburbs to offices in San Francisco. During a Dec. 12 meeting of the commission's regional network management committee, MTC staff member Kevin Chen unveiled data that showed significantly heightened congestion as would-be BART riders resorted to driving.

"This is as good a real-world representation as we currently have of a world without BART," said John Goodwin, a spokesperson for MTC.

According to the commission's analysis, both BART outages triggered regional gridlock, with pile-ups on three major westbound bridges (the Bay Bridge, the San Mateo-Hayward Bridge and the Dumbarton) and mind-numbing delays on several freeway approaches. The resulting chaos offered a dismal glimpse into one possible future for Bay Area commuting, if voters reject a transit tax in November and BART falls into a death spiral.

"This really emphasizes the importance of making sure that our public transportation system keeps running," said Adina Levin, executive director of the nonprofit Seamless Bay Area, addressing the committee on Dec. 12. "Because when there's an outage, you can really see the cost and the inconvenience in traffic congestion."

The numbers are stark. On a normal Friday in spring, vehicles average about 90 million miles traveled on Bay Area roads and freeways, an amount that rises to 92 million on a typical Friday in fall. But May 9 saw a jump to 93 million miles, while commuters drove a staggering 97 million miles on Sept. 5. On that day, the freeways that feed into the Bay Bridge became scenes of epic misery, with cars and trucks moving at a viscous crawl.

Travel times swelled by nine minutes on the Bay Bridge, with a backup of more than a mile, while the queue of cars on Interstate 80 stretched nearly seven miles, from Berkeley to the toll plaza. Drivers on Interstate 880 slogged along for three minutes more than usual before even hitting the bridge. Their counterparts on I-580 endured 12 extra minutes of sit-and-wait traffic that began in downtown Oakland. That translated into 21 additional minutes to cross the bay into San Francisco.

Those who experienced the Sept. 5 jams said they were more severe than MTC's report suggests.

"I happened to be on the I-580 corridor that day," said committee member Diane Shaw, who is also president of AC Transit's board of directors. What the numbers don't reflect, Shaw continued, are stretches of freeway beyond the commission's focal point of the Bay Bridge and the Macarthur Maze. In her memory, slowdowns started as far back as the interchange of I-580 and I-238 in Castro Valley.

"It was totally frustrating," Shaw told the Chronicle, speaking in her personal capacity rather than as a representative of AC Transit. "I actually took a picture of all the cars in front of me and posted it on Instagram with the caption, 'Why do people do this every day?'"

And as grim as it looks, MTC's data doesn't quite capture the burden on highways if transit is eviscerated. Although BART remained out of service for hours on both May 9 and Sept. 5, other systems were operating at full capacity and managed to absorb some of the need. Ferries emerged as a popular alternative, boasting ridership spikes of 31% on May 9 and 41% on Sept. 5. People also flocked to AC Transit's transbay buses, which saw an 18% ridership bump amid the May BART disruption, and a 5% increase of riders on Sept. 5.

If transit hits a fiscal cliff next year, AC Transit would likely have to slash bus service, eliminating another option for commuters. SF Bay Ferry will likely survive intact, since it draws funding largely from bridge tolls.

In spite of some ridership gains, a few transit systems suffered collateral damage when BART halted its trains. Since many people were unable or unwilling to take alternative modes to San Francisco, Muni ridership declined by 2% on May 9 and 5% on Sept. 5. AC Transit buses were more packed than usual, but the extreme volume of Bay Bridge traffic slowed bus service by up to five minutes on both May 9 and Sept. 5, long enough to make many people late to work.

What the data shows, then, is a transportation system so fragile and interconnected that it starts to degrade if one piece is removed.

"We do need to have some redundancy in our transportation system," Chen said, underscoring how hard it is for buses or ferries to sop up the damage when a major commuter rail breaks down.

Perhaps the most mind-bending conclusion of the MTC report was that the absence of BART upended rush hour as we know it. Rather than snarling at a predictable time and then receding, traffic persisted into the middle of the day. Officials have already seen this phenomenon play out since the pandemic, as remote work liberates people from 9-to-5 schedules and enables them to drive whenever they want.

Perma-rush hour could become much more entrenched if BART hits its projected deficit of up to $400 million annually, and is forced to severely cut service. Freeways would have to carry thousands of additional vehicles — up to 5,400 more cars on the Bay Bridge alone, according to a June 2024 study by BART's senior management and consultants.

Anyone skeptical about those figures need only look at the traffic snapshot during BART's service interruptions. Jams that usually peak between 7 and 8 a.m. actually became worse as the morning wore on, Chen said. By the time congestion finally eased, the evening commute was nearly underway.

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