More than 600 Alamo Rent A Car, Enterprise Rent-A-Car and National Car Rental airport shuttle buses across more than 50 North American markets to begin using at least 5 percent biodiesel. They are then looking to continue to convert more over but it seems more directed at their bus section. It will be interesting to see how this affects car rental. You as a consumer wants convenience of car rental, you have your great deal by using free discount car coupons and then you have the inconvenience of having to learn how to fill up with biofuel… Hmm There were no details of how it would work but there again they may win over some customers because of their greener world stance. It will be interesting to see how it pans out.