The head of Metro is endorsing congestion pricing for Los Angeles, telling the agency’s board of directors on Thursday that rush-hour tolls on drivers could fund free fares on public transit.

“We think that with congestion pricing done right, we can be the only city in the world to offer free transit service in time for the 2028 Olympics,” Metro CEO Phil Washington said.

It’s not clear yet how such a system would work, but if applied across the LA region, it could radically shift the way that people move around the city.

Washington suggested that a congestion pricing system would encourage more drivers to take public transit, while cutting down on LA’s notorious traffic.

Several board members latched onto the idea, including Los Angeles City Councilmember Mike Bonin, who emphasized the potential environmental benefits of congestion pricing.

“We are committing suicide as a species through climate change,” said Bonin. “Anything we do to make driving cheaper and anything that we do to make transit more expensive gets us away from the big issue.”

Los Angeles Mayor Eric Garcetti also suggested the agency should consider the option. But he acknowledged that charging new fees on drivers in such a car-dependent city would be a political risk.

“The moment you say something like congestion pricing,” he said, “there’s probably going to be nothing else in the headlines today.”

Washington endorsed the measure while presenting a report on funding options for the agency’s Twenty-eight by 28 initiative, a plan to complete 28 major projects over the next decade.

As Washington pointed out, Los Angeles already has a form of congestion pricing in place: Metro’s Express Lanes system, which charges participating drivers varying prices to use dedicated lanes on the 10 and 110 freeways.

But on Thursday, Washington laid out options for a far more expansive congestion pricing system.

One possibility would be to charge drivers when they pass through a traffic-clogged area—around Downtown or LAX, for instance. Busy corridors could also be targeted for special pricing systems that would kick in when more drivers are on the road.

Another option is VMT pricing, which has less to do with traffic conditions and depends more on how far residents drive in a given time period (drivers in this system are charged by the mile).

According to Washington’s report, these systems could produce between $12 billion and $104 billion over the next decade, with VMT pricing predicted to be the most potentially lucrative option.

Washington suggested that, with fee systems like these in place, Metro could not only speed up eight key projects included in the Twenty-eight by 28 initiative, but could also subsidize fares for riders “forever and ever.”

Members of the board said this would be a crucial part of ensuring the success of such a system.

“Whenever we are going to be looking at congestion pricing,” said Los Angeles Councilmember Paul Krekorian, “equity demands that there has to be a free or nearly-free alternative.”

Board Director Sheila Kuehl was slightly less enthusiastic about the proposal, pointing out that residents in areas poorly served by public transit would be forced to pay more to drive, without being able to benefit from free train and bus rides.

Other cities have imposed congestion pricing systems, including London, Stockholm, and Singapore (none offer free transit service). No U.S. city has instituted a region-wide congestion pricing policy, though New York is considering one.

Several transit experts spoke to Metro’s board on Thursday about the proposal.

Martin Wachs, professor emeritus of urban planning at UCLA, told the board that congestion pricing is the only strategy for reducing traffic “that has been proven to work in every city where it’s been applied.”