Can living near a train station save your house? Researchers looked at mortgage defaults in three cities and found something curious -- the chance of foreclosure is higher in neighborhoods more dependent on cars, according to a report by the Natural Resources Defense Council, which included data from Chicago's Center for Neighborhood Technology. The report examined 40,000 mortgages in Chicago, Jacksonville and San Francisco. The link became more obvious in looking at foreclosures after July 2008, when gas spiked over $4 a gallon, said CNT President Scott Bernstein, who studied foreclosures in the Chicago area. Bernstein found that gas price spikes provide an "early warning" of a rise in foreclosures in car-dependent communities.