Late-night, weekend transit service between San Francisco and the East Bay is about to be expanded, thanks to state funding. This December, a year-long AC Transit pilot program, in collaboration with Bay Area Rapid Transit, will offer extended hours and routes for the current late-night bus service. But officials are not heeding calls for a 24-hour rail service, which experts say would be a difficult undertaking.

Starting in December, AC Transit’s “Owl Service” will expand the frequency and destinations of late-night bus service on Friday and Saturday nights. Buses will travel as far west into San Francisco as 24th and Mission, and as far east as the Pittsburgh-Baypoint BART station. Those buses will make all stops along the Pittsburgh-Baypoint BART route from 12:30 am to 2:30 am on those nights. “We already run service from San Francisco to the East Bay every day,” said Clarence Johnson, spokesperson for AC Transit. “But there were some parts of the East Bay that people weren’t able to get to.”

After assessing the needs of its ridership earlier this year, BART received nearly a half million dollars from the Metropolitan Transportation Commission to address transit concerns. Riders expressed a growing need for expanded public transportation on Friday and Saturday nights from San Francisco to the East Bay. The agency currently shuts down all trains shortly after midnight, and does not continue service until 4 am. “The only option for them was to have a bus service,” said Johnson. “Since we were already running service to and from SF, it was only logical that the two of us team up to provide the service.”

The expanded service will use the agency’s 60-foot long buses, and employ its current staff of drivers, who will undergo training to learn new routes. Johnson said that if necessary, AC Transit will consider utilizing larger coach buses, called “cruisers,” that can carry more passengers. The cost of riding will not change; transbay nighttime service is now $4.05 regardless of where along the line passengers board or disembark.

The later buses are expected to serve pre-dawn commuters, many coming from work, or club and bar patrons leaving for the night. When asked if AC Transit was concerned about disorderly conduct from intoxicated passengers, Johnson said it’s had few—if any—problems with passengers since it began nighttime service in 2005. “There’s no reason to believe that there’s going to be anything inherently dangerous by extending service,” Johnson said.

A perennial grievance among many Bay Area commuters is that BART does not operate 24 hours a day. BART officials say that when the system was built in 1972, it wasn’t designed to operate overnight. It only consists of two tracks, leaving no alternate rails for trains to run on while the other is undergoing maintenance. “To get inspections done and maintenance done, you have to completely shut down the tracks,” said Jim Allison, spokesperson for BART. “There’s no way we can run train service for 24 hours a day, so buses seemed the logical way to go.”

However, once the extended service goes into effect, the Bay Area will continue to face major transportation infrastructure problems. As reported by the San Francisco Chronicle in August, the region’s roadways are highly congested and BART trains are filled to capacity during peak commute hours. And as the region’s population continues to increase, those issues will likely be compounded, a problem BART officials acknowledge. “If we could go back in time and create more tracks, it would make a difference,” Allison said. “But we’re constrained by the system that we have.”

So why not build more tracks in order to provide 24-hour service? Experts say cost is a factor. “It’s very, very expensive in urban areas to cut-and-cover underground rails,” said Elizabeth Deakin, professor of City and Regional Planning and Urban Design at UC Berkeley. What’s more, doing so would probably require building above-ground structures like subway exits or even new stations. “The places where you need it in the East Bay and San Francisco, that’s really expensive real estate,” Deakin said.

Deakin points out that there are many rules and regulations that have gone into effect since the original BART system was built in the 1970s. “There’s Prop. 13 and tax restrictions and lots of other things California has done since BART was built that constrain investments,” she said. Proposition 13, passed in 1978 by nearly two-thirds of California voters, is a complex law that dramatically reduced property tax rates. The law is often criticized because it created high tax rates for individuals and businesses purchasing real estate at market value, thus discouraging the investment necessary to spur economic growth.

Entrepreneurs are aware of the need for nighttime transportation service and are itching to get in on the potential of that market. The San Francisco start-up Night School proposes using off-duty school buses to transport commuters between San Francisco and the East Bay from midnight to 4 am on weekends. But the company is struggling to come to a licensing agreement with the California Public Utilities Commission and has not yet announced a formal launch. In the meantime, ride-sharing services like Uber and Lyft continue to grow and have become a viable option for late-night transportation for many commuters.

Transit agencies and infrastructure experts agree that a 24-hour subway system is a costly and complicated venture that is not likely to happen anytime soon. Deakin said that for now, buses are an easy, affordable and safe alternative for getting people where they need to go. “I know many of my students are really looking forward to having that service, because they’ll feel safer and don’t want to drive,” she said.