5. Washington, D.C.
Number of car-sharing locations: 521
Top neighborhoods: Columbia Heights, Capitol Hill, Downtown
Sure, the Metro works just fine for the average commute, but this is a town with a reputation to keep. The cabs here work just fine too, but that didn't prevent D.C. residents from flipping the concept on its head by embracing Uber, the online car service that will send a black, luxurious bit of rolling awesome to pick you up anywhere in the city. It's a similar situation with car-sharing services, which can be more convenient than waiting for a train that doesn't go directly to your destination and less costly than a car service. Car2go, for example, offers free parking at any meter in D.C. as one of its key perks, which is no small deal in a town where parking's at a premium as it is. Granted, Car2go Smart cars are big white-and-blue Car2go ads, but that's secondary to a cheap, efficient and -- most importantly -- punctual little splurge.