The Brookings Institution Metropolitan Policy Program has released a study showing that nearly 700,000 households in the 100 largest U.S. metropolitan areas do not have access to either public transportation or a private vehicle.

In contrast, more than 90 percent of the 7.5 million zero-vehicle households in these regions live in neighborhoods with access to public transit service—although on average they can reach only 40 percent of jobs within 90 minutes when using transit.

The report, Transit Access and Zero-Vehicle Households, uses data from the American Community Survey and 371 public transit providers to reach this conclusion.

According to Brookings, the Los Angeles-Long Beach-Santa Ana, CA, corridor has the highest coverage rate for no-car households, 99.1 percent, while the Atlanta region has the lowest, 68.5 percent.

“If you’re going to keep afloat during the recession, you have to be able to get to work,” said Adie Tomer, senior research analyst and author of the report. “We knew there were pockets of households who are economically hampered by the fact that they own no car and have no access to transit, but we didn’t fully understand the true scope of the problem until now.”

Tomer placed the figure in context by noting that 700,000 households is a larger number than the population of Columbus, OH, or San Antonio, TX. “These people are terribly constrained in earning a living, getting to the store, or taking their kids to day care,” she continued. “If this many people were facing a public health scare, this country would be in crisis mode. We need to approach this problem with similar urgency.”

Transit Access and Zero-Vehicle Households is the first in a series of three studies following the release in May of Brookings’ Missed Opportunity report, which found that transit services fall far short in connecting workers to jobs. The next two studies will focus on access to transit from public housing and how transit serves employers’ needs.

The full text of the report is available online.