NEW YORK (AP) — The ability to access a car quickly and give it back after a few hours is exploding in popularity among both college students and city dwellers. Zipcar created the car-sharing concept in 2000. By the end of the decade car-sharing had caught the attention of the two largest U.S. car rental companies as Enterprise and Hertz started competing services. And this week, Avis, the nation's No. 3 car rental company, jumped into by offering nearly $500 million to buy Zipcar. Read more: http://www.sfgate.com/news/article/A-look-at-the-pros-and-cons-of-car-sharing-4168037.php#ixzz2HAtWjxOx