Can mass transit run without humans? Two major US cities are weighing the option

Despite the growing prevalence of driverless vehicles such as robotaxis across the United States, virtually every mass transit network still relies on a human driver or operator onboard.

Now, two major American cities are seeking to alter that pattern.

Officials in Washington, D.C., recently advanced a proposal that could allow computers to fully operate one of its subways, while Los Angeles is working to construct a completely automated line.

The D.C. and Los Angeles initiatives, which will take years to implement and still confront financial and technical hurdles, arrive during an intense ongoing debate regarding the safety risks and benefits of automated rail and whether heavy initial upfront expenses justify long-term labor savings.

Supporters describe the effort as long overdue, pointing out that American municipalities lag far behind international systems that run unattended subways, metros, or buses, including several cities in Europe and Asia, alongside major networks in Canada, Australia, South America, and the Middle East.

"It should be much harder to automate something that’s on-road, that has all of these various obstacles coming at it, compared to a fixed-rail system," said Baruch Feigenbaum, senior managing director of transportation policy at the Reason Foundation, a libertarian think tank that has advocated for transit automation.

"I don’t know a nice way to say this, but basically the transit world is where innovation goes to die."

Widespread transit automation has been slow to develop in the U.S. Only in recent years have driverless road vehicles from companies like Waymo, Tesla, and Zoox taken the technological lead in the U.S. ahead of rail-based transit networks.

Although operators have consistently staffed the Metro subway system in Washington, D.C., trains operated with partial automation features when it first opened 50 years ago.

Following a fatal 2009 crash, those systems were turned off, before being restored over the past two years.

Now, officials in the capital have renewed their push for full automation on Metro's Red Line. Meanwhile, an environmental review is underway in Los Angeles for an automated track along a new underground heavy-rail route through the rugged terrain of the Santa Monica Mountains.

Honolulu is already operating an elevated driverless line, which stands as the most expansive automated transit system in the U.S. It will stretch 19 miles upon completion, surpassing earlier pilot projects opened in Detroit and Miami during the 1980s, a monorail servicing Las Vegas Strip hotels, and smaller airport shuttle networks.

An automated monorail that previously operated in Memphis, Tennessee, shut down years ago. Meanwhile, the driverless Jacksonville Skyway will indefinitely halt operations soon due to budget cuts, despite initial ambitions for an expanded system.

Fatal crash slowed earlier automation efforts After nine people were killed and many others injured in a 2009 train collision near the Fort Totten station on Washington's Red Line, the National Transportation Safety Board attributed the crash to a maintenance flaw within the automated signaling system designed to separate trains.

Randy Clarke, CEO of the Washington Metropolitan Area Transit Authority, noted in an interview with The Associated Press that the Fort Totten issue was unrelated to the cruise control-like system restored on the Red Line in 2024 and across other Metro lines last year.

Still, he acknowledged that for many years the crash "paralyzed" Metro's plans for further automation.

"That was a big failure, there’s no question. We do not do anything like that now," said Clarke, who called the current system "highly regulated, highly documented, very proficient."

Trains could potentially run without a human operator inside the cab as early as 2033 under a nearly $1 billion plan backed by Metro's Board of Directors in April to upgrade the Red Line with safety features, including protective barriers that prevent passengers from reaching the tracks.

Clarke said that even if workers are not needed to physically drive the trains, staff will still be required to maintain tracks and respond to emergency situations.

Unions have remained strong critics of automation. John Samuelsen, a former employee in the New York subway system who now serves as international president of the Transport Workers Union, said labor unions have resisted automation efforts in New York and elsewhere, calling them "a catastrophe waiting to happen."

"Passengers will be left dealing with a self-evacuation, which is a disaster in a system which runs on a third rail," Samuelsen said.

To relieve heavy traffic bottlenecks for commuters, Honolulu opened its Skyline automated light metro system three years ago and expanded it last year.

Vance Tsuda, the system's project director, said there has not been a single crash or injury tied to automation. Even hybrid systems are less safe than a completely automated network, he argued, stating that a human operator is far more likely to overlook a hazard like an open door before clearing a train for departure.

"If you have somebody making that decision, they could make a wrong decision," Tsuda said.

However, David King, an associate professor of urban planning at Arizona State University who researches automated transportation, said the success rate must remain flawless to preserve public trust.

That is why the Fort Totten crash and other automation incidents set the technology back so significantly, he said.

"We allow a certain amount of failure with private industry that we don’t tolerate when the state does it," said King, pointing to several rockets blown up by Elon Musk's SpaceX — a record he argues would devastate NASA's budget if experienced in the public sector.

Perhaps the most ambitious transit automation effort currently underway in the U.S. is the underground line Los Angeles officials voted to recommend beneath the Santa Monica Mountains.

The area remains one of the country's worst traffic bottlenecks, with the mountains separating the busy Westside commercial hub from the San Fernando Valley.

An existing subway already runs under the same mountain range near Hollywood, but that line operates with a driver onboard. The new proposal, which is undergoing environmental review, would utilize shorter, more frequent trains, according to Cecily Way, who oversees planning for the Sepulveda Project for LA Metro.

Like the project in Washington, the new Los Angeles route would include platform screen doors to protect passengers from approaching trains.

Feigenbaum with the Reason Foundation said automating a major transit corridor in cities like Los Angeles or Washington could open the floodgates for other municipalities.

"It sends a signal that this is technologically doable and this is something that maybe other systems are going to want to strive for," he said.