Could this be the end of $3 parking at BART lots?

The rush hour trains are packed. The carpeting is gone, the seat upholstery is on its way out. But for nearly two decades, BART riders have clung to one enduring perk: $3 parking.

Now that, too, may go. The Board of Directors may soon raise prices to open more space in station lots, nine of which fill up before 8 a.m. each weekday. All but two of the rail system’s 36 lots are 95% full during the day, and 40,000 people linger on a waiting list for monthly parking permits.

BART rents most spaces by the day, setting aside a portion for carpools and permit holders. The agency charges far less than market rate. In Lafayette, meters near BART cost $5 a day, and a privately run garage near the Walnut Creek Station charges $15 to $18 a day for each spot.

Several board directors are pressing for higher parking fees during commute hours.

“We don’t charge enough,” said Director Rebecca Saltzman, noting the side effects of cheap parking spots. The lots fill up early in the morning, and people who can’t arrive before 8 a.m. wind up circling the blocks.

On Thursday, BART directors debated demand-based pricing, which would probably mean more expensive parking on weekdays and lower prices on weekends, when fewer people ride the trains. Directors from the transit-rich urban centers favored the concept, though some of the stations they represent lack parking lots altogether. Their counterparts from the more auto-dependent suburbs were wary.

“We are not serving ridership if we keep decreasing the parking supply and raising rates,” said Director Debora Allen, whose district encompasses central Contra Costa County.

Besides possibly adjusting rates, the directors are grappling with the problem of people who park their cars but don’t pay — taking up 10% to 15% of the available spaces, according to the agency’s parking program manager, Ryan Greene-Roesel. The directors have not said when they will decide on a new policy.

Saltzman stressed that BART should not treat parking as “a big cash cow” — instead, she wants most of the returns to fund bus service to carry people to BART. She and other supporters of the variable pricing say it would help manage a hot commodity that will only become more scarce as BART fills its lots with housing. Armed with a new state law that loosens development restrictions on BART property, the agency is planning projects at 14 of its 48 stations, including El Cerrito Plaza, Hayward, Ashby and North Berkeley.

To Saltzman, increasing the price of parking is also a form of justice for BART riders who don’t drive to the stations. For years, their fares and tax dollars have helped subsidize parking spaces. The land BART uses for parking lots is worth far more than the revenue the spaces generate. The agency also has to pay for enforcement, paving, striping, and maintenance of these spaces, and those costs add up.

Detractors, including many motorists and politicians representing cities along the BART line, say higher prices will chase people away from BART and steer them onto freeways. Some motorists say a parking fee hike would be unfair for disabled and elderly people who have to drive to the stations because bus service is spotty or nonexistent.

Director Mark Foley, who represents the east Contra Costa County area of the rail system, empathizes with riders who have no alternative but to drive. He arrives at Antioch Station at 5:27 a.m. each day to find a space — parking there is so competitive that the transit agency will open a second lot with 850 more spaces this year. BART converted a piece of its land to build the lot, at a cost of $16.4 million.

While Foley wants to raise parking prices, he doesn’t want them to skyrocket. And he is pushing for supplementary transit service, such as buses or shuttles, to carry people to stations.

“The biggest challenge is trying to find a solution that ensures there is parking through mid-morning, but at the same time doesn’t price people out of being able to take public transportation,” he said.

Foley and Saltzman said they would support a parking discount for low-income people.

That wasn’t enough to placate Miguel Saldaña, who was rushing to pick up his car from the garage at El Cerrito del Norte Station on Thursday evening. Saldaña lives in Richmond and drops his kid off at daycare before taking BART to work in Oakland. He can’t get to the daycare on a bus.

“Frankly, if the price went up, it would discourage me from taking BART,” he said.

Nina Lovejoy takes the bus to El Cerrito del Norte from her home in Richmond, but even she frowned at the specter of a parking fee hike.

“BART is already too expensive,” she said. “This could really hurt people.”

In some cities that BART serves, even a small parking fee increase would hit stout resistance. Lafayette City Councilman Cameron Burks routinely accuses BART of being philosophically against parking, and he points to the agency’s efforts to develop its parking lots as evidence of a hostile stance towards motorists.

“Raising the price even a few dollars is material to a lot of people, so you’re going to see them drive into the city and make deals with parking garages,” Burks said Thursday.

Although Burks doesn’t use BART to commute, he’s noticed that the Lafayette Station lot fills up early each morning — not just with Lafayette motorists, but with super-commuters driving in from as far away as Dixon (Solano County) or the Central Valley.

If the price of parking goes up, Burks assumes those people would simply drive to work. And for those hunting for a parking spot and willing to pay a higher price, that could be a good thing.

Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan