The Avis rental car company now has plans to purchase a car sharing company called Zipcar. The Zipcar company primarily targets Universities and Metropolotian areas in which people who have a membership can rent a car by the hour. The Zipcars are usually located on campuses and near subway stations and its member's can make reservations online or use a smart phone app and go directly to the car for pickup without having to go to a rental car counter. The zipcar rates include insurance costs and gas for up to 180 miles. Here is a link to an article in USA today that describe's Avis's plans to expand the Zipcar service. http://www.usatoday.com/story/money/business/2013/01/02/avis-buying-zipcar/1803717/
Hertz also offers a similiar service called "Hertz on Demand"