Urban planners have long considered public transportation the best remedy for traffic congestion, but many of the nation's largest mass-transit systems simply aren't up to the task.
They lack the money to keep up with basic maintenance, let alone modernize and expand to attract more riders and take pressure off the highways connecting growing cities and suburbs.
Continue Reading Below
Consider Boston, where the oldest American subway system began operating in 1897. During a winter of record-setting snow, the Massachusetts Bay Transportation Authority was often paralyzed, its antiquated equipment overwhelmed by the elements.
By late February, "the T," as locals call it, had less than half of its fleet available. Service was not fully restored until the end of March.
At the height of one storm, police helped ferry doctors and nurses to hospitals so emergency rooms could stay open. Schools closed. Businesses suffered, along with countless workers, especially hourly wage employees who couldn't get to their jobs.
Among those was Patricia Varon's disabled son.
"It was a loss of income for him," she recalled. "He waited for hours, and the train never came."
What happened in Boston over the winter was extreme, but transportation experts and policymakers say it's emblematic of chronic underinvestment in urban transit systems at a time when demand is growing in many areas.
"Boston is a case in point that we're undershooting the target, and we've been doing it year after year after year after year," U.S. Transportation Secretary Anthony Foxx said in a recent interview.
Under ideal circumstances, public transit systems would extend their reach, offering more trains, buses and ferries, longer hours and new routes serving a wider geographical area. Newer systems in cities such as Los Angeles and Denver have plans to do just that.
But the so-called "legacy" systems serving Boston, New York, Philadelphia, Chicago, San Francisco and Washington face a dilemma: Should they use limited money to shore up their creaky infrastructure or stretch it to expand service as populations grow?
In Boston, some critics of the T say the agency dug itself in a hole by expanding even as its core infrastructure deteriorated, leaving the nation's fifth-largest transit system heavily in debt.
The Pioneer Institute, a nonprofit research group in Massachusetts, found the T added more commuter rail miles than any comparable U.S. system in the past 25 years, but with questionable results. It found that ridership on the 394-mile commuter rail network actually dropped between 2003 and 2013.
A task force assembled by Gov. Charlie Baker after the winter storms called for a moratorium on most expansion, a stance criticized by some transit advocates.
The debate is taking place as the desire for more mass transit grows nationwide.
Miles traveled by passengers on transit increased by 15 percent between 2004 and 2012 while highway travel was stagnant, according to the American Public Transportation Association.
Moreover, a 2014 survey of millennials in 10 large U.S. cities found that 3 in 4 young adults envision living in a place where they will not need a vehicle to get around. Yet many also rate their own regions as "fair" or "poor" when it comes to public transportation options, according to the study by The Rockefeller Foundation and Transportation for America.
In the San Francisco Bay Area, population growth dictates expansion for Bay Area Rapid Transit.
But the BART system also has $4.8 billion in unfunded capital needs over the next decade, including replacement of its aging fleet. Spokesman Taylor Huckaby noted a "fundamental tension" between maintenance and expansion.
"It is often easier to generate support and attract funding for new projects than for maintenance projects because riders and other stakeholders tend to take for granted current infrastructure and service levels," Huckaby wrote in an email.
The 43-year-old system is moving forward with expansion projects, including one to Silicon Valley, while also setting a goal of increasing the total seating capacity of its fleet by nearly 50 percent.
The Federal Transit Administration estimates the cumulative national cost of fixing or replacing transit assets that are in disrepair or operating beyond their useful life at $87.7 billion. About a quarter of the nation's rail and bus assets are in poor or marginal condition, according to the agency.
Art Guzzetti, a veteran of transit agencies in New Jersey and Pittsburgh and now vice president of policy for the transportation association, said officials are often forced to adopt a Band-Aid approach to maintenance, stretching the life of existing assets just to meet the demands of providing daily service to commuters.
Most rail vehicles are supposed to have a minimum useful life of 25 years, but some urban systems run trains that date as far back as the 1960s.
Maintaining and modernizing core service is the top priority for transit systems if they are to retain the public's trust, but the case for expansion cannot be ignored, said David Goldberg, communications director of Transportation for America, a national advocacy group.
"You can't really afford to let it fall apart while you seek money for more capacity," he said. "But that said, in this day and age, if you rest on your laurels and are not looking to expand where the population and the economy warrant it, then you are going to fall behind."
Associated Press writers Joan Lowy in Washington and Justin Pritchard in Los Angeles contributed to this report.