The advocacy group pushing for high-speed rail in the United States begins its annual meeting today in Los Angeles. California is something of a poster child for the U.S. High Speed Rail Association, thanks to a $68 billion plan for a bullet train to connect L.A. and San Francisco.

But many hurdles remain for advocates pushing for greater high-speed rail nationwide. To get there, the U.S. would need to prioritize rail over highway spending, said Stan Feinsod, of the Mineta Transportation Institute at San Jose State. 

“You can’t buy more lanes,” he said. “Passenger rail is a hell of a lot less expensive than building out your highway network, and trying to add lanes and lanes and lanes. It just doesn’t work.”

Rail will also have to overcome the threat posed by driverless cars and more efficient air travel, said Cato Institute senior fellow Randal O’Toole.

“Rail makes a lot of sense for freight,” he said. “It really doesn’t make much sense for passengers anymore.”