Coupon valid for a one time, one car group upgrade on an intermediate (group C) through a full-size four-door (group E) car. Maximum upgrade to premium (group G). Offer valid on daily, weekend, weekly and monthly rates only. The upgraded car is subject to vehicle availability at the time of rental and may not be available on some rates at some times. Coupon valid at participating Avis locations in the contiguous U.S. One coupon per rental. A 24-hour advance reservation is required. May not be used in conjunction with any other coupon, promotion or offer. For reservations made on Avis.com, upgrade will be applied at time of rental. Renter must meet Avis age, driver and credit requirements. Minimum age may vary by location. An additional daily surcharge may apply for renters under 25 years old. Fuel charges are extra. Rental must begin by 12/31/2011.