Traffic congestion and air pollution have long spurred transportation officials and environmental advocates to urge, cajole and beg commuters to switch to public transit. Still, the vast majority of Bay Area commuters wouldn't budge from behind the wheel.
As gasoline prices climb past $4 a gallon, however, commuters are moving to public transportation in huge numbers, breaking records on BART, commuter trains and transbay bus routes.
Whereas public transportation used to be equal to the task of transporting one in 10 of the Bay Area's commuters, evolving into a major rival of solo driving is proving to be as painful for commuters as it is delightful for public transit advocates.
Parking at many BART and train stations is filling up earlier and earlier. Seating is becoming a luxury on more peak-hour trains and buses, and transit officials are wondering how to increase service at a time when state and local budgets are strapped. The economy is on edge and filling buses' diesel tanks has never been more expensive.
"Just getting 15 miles per gallon from here to Santa Clara was getting to be too much," said Brian Heidl, a mechanical engineer, as he waited for the 6:42 a.m. Altamont Commuter Express train in Livermore on Wednesday.
"I was practically paying $400 a month just in gas," Heidl said, to keep his 1987 Ford Ranger pickup making the 60-mile trip along some of the area's most congested freeway segments, on Interstates 580 and 680.
Now, he pays about $225 for his monthly ACE ticket "and I get to sleep the whole way and not have to worry about the traffic."
But veteran ACE riders have noticed that it's getting more difficult to find a seat and bicyclists are lamenting overcrowding on the train's onboard bike rack. On the Gilroy-to-San Francisco Caltrain service, "we have to turn bikes away every day," said railroad spokeswoman Christine Dunn.
Across the nation, skyrocketing gas prices have complicated America's love affair with the car. Motorists drove 0.4 percent fewer miles in 2007 than the previous year, the first time without an increase since at least 1982, the first year mileage was tracked in a report by the Federal Highway Administration. "It's simply becoming too expensive for some people to drive a car on a regular basis," said Virginia Miller, a spokeswoman for the American Public Transit Association. "People are voting with their feet for public transit."
But like a newly elected president, transit systems will be hard-pressed to meet all the needs of their new constituents.
New BART riders, for example, are finding rush-hour trains more packed than ever, leading the agency to experiment with removing seats on some cars to make more room near the doors for standing riders.
Public transit ridership has grown rapidly since gas prices regularly exceeded $3 per gallon in mid-2005, and growth accelerated this year as prices neared or surpassed $4 a gallon.
The biggest surge in the number of riders is on rail systems such as BART, which carry long-distance commuters who have the option of driving but now feel an especially sharp pinch at the pump.
Across the nation, commuter rail systems such as ACE, which runs from Stockton to San Jose, saw an average ridership gain of 6.1 percent in 2007, according to the transit association's statistics.
In the Bay Area, where gas prices have been among the highest in the nation, the effect has been dramatic. Riders have flocked to ACE and Capitol Corridor trains, which run from the Sacramento area to San Jose via the East Bay. On both services, ridership rose 13.6 percent in the first quarter of 2008 compared with the same quarter last year.
On bus systems, which often carry many people who have no other means of getting around, ridership nationally climbed about 1 percent last year.
AC Transit, which serves large lower-income, non-driving populations in Oakland, Richmond and other areas stretching south to Fremont, is such a system. Its heavily subsidized local ridership has stagnated after service cuts and other constraints. But many of its transbay bus routes, which cater to "choice" riders with private vehicles, have seen ridership increases as high as 20 percent in the past year.
Although most of the drivers making the switch are turning to public transit, other modes also appear to be growing. On the Bay Bridge, for instance, carpool traffic grew 5.2 percent in the nine months ending with March, even as overall traffic declined.
Auto traffic in the Bay Area has declined before, most significantly when the dot-com bubble burst, leaving far fewer jobs to which people would commute. That trend was accompanied by a drop in transit use, too.
The Peninsula's popular Gilroy-to-San Francisco Caltrain service saw its ridership tank after hitting its dot-com peak in 2001.
Seven years later, Caltrain finally surpassed that record, hitting 3,993 average daily riders in February.
"We're already seeing some of our express trains during the peak hours at capacity," Dunn said. "We've added as many trains as we can add. We have scheduled as close as we can schedule," with eight trains passing through Millbrae during rush hour.
The agency is acquiring eight new cars by the end of the year to add to existing trains, Dunn added, but it will be many years off, with the advent of a closely controlled electric-powered system that it will be able to run trains more frequently.
One of the more daunting challenges posed by the surge in riders involves getting riders from often sprawling suburban neighborhoods to use public transportation.
The current trend can be painfully evident to commuters who show up at the Pleasant Hill BART Station after 7:45 a.m.
BART regular Gary Alexander once became so exasperated upon finding no parking there that he returned to his Walnut Creek home and called a taxi to drive him back to the station.
"The parking absolutely is getting worse," Alexander said. "You learn to play the parking game. You get here early, or you have to have another plan."
"Parking is a constraint," said BART General Manager Dorothy Dugger, "but we need to look at parking as one part of the challenge in improving access to our stations." Bus, bike and foot traffic must also factor in, she said.
Dugger said BART's ability to move passengers would be taxed if ridership continues to climb 4 percent or more for a decade, which is twice the rate of BART's historical growth rate.
"We have capacity now," she said. "But we're in the same boat as a lot of the older transit systems. We're talking about the need for adequate levels of federal support to reinvest in these systems, as well as to meet the demand for increased capacity."
BART is taking some measures for short-term relief. Train system managers have started a pilot project to remove as many as six seats near the doors of as many as 80 cars. The experiment seeks to determine whether the extra space will move trains more quickly through stations by speeding up the loading and unloading of passengers.
Although experts predict that high fuel prices will persist as worldwide oil demand grows and supply struggles to keep up, commuting experts such as Alan Pisarski caution that the allure of the personal vehicle is still strong.
"There's an argument to be made that gas prices aren't going back down, but I'm not so sure," said Pisarski, author of the "Commuting in America" report series read by transportation officials across the nation. Pisarski noted that past dire predictions about oil supply, during the oil shortages of the 1970s and early 1980s, proved premature.
"When gas prices recede," he said, "people snap back to their previous behavior."
BART operators painfully recall expecting continued robust growth after the late 1990s, only to watch riders dwindle along with dot-com jobs during 2002, 2003 and 2004.
"People don't change their habits overnight simply because the price of gas this week went over $4 a gallon," said BART spokesman Linton Johnson. "We could have sky-high gas prices, but if there are no jobs or if the freeways are empty, we won't have as many riders."
Some transit operators say they expect to hold on to many new riders, though.
In the Seattle area, rail ridership stayed 10 percent higher after the completion of a major freeway project last year that impeded traffic for weeks.
"Once they tried public transit, they thought it was worth the cost-saving and convenience," said Linda Robson, a spokeswoman for Sound Transit, which runs trains and buses in the Seattle and Tacoma areas.
Bay Area commuters got a similar push to try public transportation last year when a MacArthur Maze freeway ramp collapsed in a fiery gasoline tanker truck accident and construction closed the Bay Bridge during Labor Day weekend.
Ridership broke records on BART during those periods, and it remained high after the blocked structures reopened.
Public transportation in California is funded through a complex set of programs and formulas.
In the Bay Area, it costs more than $2.2 billion a year (2006-07 fiscal year) to operate two dozen rail, bus and ferry services.
Nearly $604 million of that comes from fares, and the remainder comes from county sales taxes, property taxes, state sales tax on gasoline, federal transit grants and, showing how complicated the system is, the largest category is one the Metropolitan Transportation Commissions calls "other."
Although most of California's transit services get their biggest chunk of funding from local sales taxes, as do SamTrans and Santa Clara County's Valley Transportation Authority, the Bay Area has some big anomalies. San Francisco's Muni System got more than half of last year's $580 million budget from city general funds, and the East Bay's AC Transit gets a quarter of its $300 million operating budget from property taxes.
One of the most unpredictable sources is from the state government. It's either feast or famine for two reasons: One, it's from the sales tax on gasoline, which has ballooned in recent years along with gas prices, and two, that big bundle of revenue is a tempting pot of money for the governor and state legislators to raid for other purposes during tough budget years such as this one.
Transportation officials estimate the gas sales tax haul to reach $2.5 billion for the fiscal year starting July 1, but key state officials are already discussing the possibility of diverting those funds to cover the budget shortfall for nontransit programs.