Kansas City, Missouri is on the verge of becoming the largest U.S. city to offer completely free public transportation.

Could Los Angeles—home to the nation’s second-largest bus system and a growing rail network—be next?

Phil Washington, the head of LA’s countywide transit agency, proposed last year that by tolling drivers, the agency could offer free rides on trains and buses as soon as 2028—a strategy he enthusiastically predicted would get cars off the road and build the agency’s rider base, cutting down on carbon emissions in the process.

“We’re talking about saving mankind here,” he said.

Since then, Metro has launched a study of possible toll prices and locations and will soon begin analyzing new public transit pricing options as it plans for the next decade.

Right now, passenger fares ($1.75 per ride) add up to only around $300 million each year—just a small percentage of the nearly $2 billion it takes to keep Metro’s armada of trains and buses running. That means even a fairly limited toll system could easily generate the revenue needed to make transit free.

But would free fares create more problems than they’d solve?

A policy analysis published this year by research and advocacy organization TransitCenter makes the case that cities like Los Angeles should focus on other ways to improve people’s experience on public transportation.

“The agency could technically get by without fare revenue, but the scheme would only work if massive funding was injected into improving current service, rather than into splashy, long-term rail projects,” the report says.

TransitCenter points to survey data suggesting that public transportation users nationwide—including low-income passengers, who make up the vast majority of Metro's rider base—would prefer faster, more reliable service over a fare reduction.

Teo Wickland, a PhD student in urban planning at UCLA, researched the concept of free fares while working on the California Statewide Transit Strategic Plan.

He says that eliminating rider charges could improve service on its own, particularly on buses, where the boarding process is slowed every time a rider struggles to find their TAP card, or reaches into their pocket to come up with exact change.

A fare-free system “makes buses operate faster,” Wickland says. “And in some cases it means you can have more buses per hour going in each direction because they finish the route sooner.”

Eliminating fares, he predicts, “is definitely going to increase ridership.”

That’s a big incentive for Metro, which has been looking to reverse a years-long slide in ridership on its trains and buses.

Without fares, the system could be more accessible to first-time riders, who wouldn’t have to struggle with a finnicky TAP card machine before boarding. Regular riders, particularly those with low incomes, might be encouraged to ride more often, since they wouldn’t have to worry about sticking to a travel budget.

Right now, Metro offers subsidized fares to low-income riders, students, seniors, and passengers with disabling conditions. But Eli Lipmen, director of development and programming for transit advocacy group Move LA, says that Metro’s discount program is tricky to sign up for and that the savings for riders don’t go far enough.

For a single adult making less than $36,550, the cost of a monthly pass is still $76.

“Even with that discount, that can be a large share of the income they have,” says Lipmen. His organization is pushing Metro to make transit free for students as soon as possible—something he says could also attract more riders to the system.

But could a surge in rider demand leave vehicles crowded and overtaxed?

Brian Taylor, director of UCLA’s Institute of Transportation Studies, says the big question is what happens during rush hour.

During peak commuting hours, nearly all of Metro’s train and bus lines come more frequently than during other parts of the day in order to carry the large number of riders who board during these times. As a result, it’s more difficult to add service during these times—because most of the agency’s vehicles are already in use.

Taylor says it’s relatively easy for transit agencies to handle ridership increases in off-peak hours, because buses and trains may not be running full; if they are, additional trips can be more easily added because the agency has vehicles to spare at these times.

If a huge number of new people start riding during rush hour, however, the agency would have to buy more vehicles and hire more drivers—or riders would have to get used to buses and trains that are packed to capacity.

What’s unclear at this point is whether making fares free would attract more high-income riders, who disproportionately tend to ride during peak hours.

“When you take away all the cost burdens, you may incentivize people to use transit that’s very expensive to provide,” says Taylor. Ideally, he says, the ridership gains would be distributed throughout the day. But it could be difficult for Metro to predict how eliminating fares would impact the whole system without trying it out.

“It’s a little bit of a crapshoot,” says Taylor.

Riders with higher incomes are also more likely to use ride-hailing apps such as Uber and Lyft, which Metro officials say have drawn some riders away from transit.

Regina Clewlow, founder and CEO of shared mobility data company Populus, co-authored a 2017 UC Davis study linking ride-hailing companies to increases in the number of trips taken and miles driven in major cities.

She says that Metro will have to do more than offer free fares if it wants to compete with Uber and Lyft for potential riders.

“People are making decisions about how to get around in cities based on convenience, time, and money,” Clewlow writes in an email. “I suspect that eliminating transit fares won’t be enough to move the needle for the majority of people.”

But Clewlow says a combination of driver tolls, new bus-only lanes, and more reliable service could begin to “make transit a more attractive option over Uber/Lyft and driving one’s own car.”

Wickland agrees that if local leaders are truly invested in getting people out of private vehicles and on to trains and buses, these kind of investments are the best bet.

“If we have to buy some more buses and hire more drivers, that’s a good thing,” he says. “If there’s a real commitment among leaders to fund a sustainable transportation system, it will be very easy to find the money.”