Most car rental offices offer a range of vehicle sizes to suit a variety of budgets and space requirements and some additionally offer specialized vehicles to suit its location such as convertibles, prestige models, hybrid/electric vehicles, or SUVs and passenger vans. At major airports or in larger cities, some independent car rental agencies offer high-end vehicles for rent. Some specialized companies offer older vehicles at reduced prices.
To allow for a uniform classification and easy comparison of car rental prices, the Association of Car Rental Industry Systems and Standards (ACRISS) has developed the ACRISS Car Classification Code coding system. This describes the size, door count, gearbox type (manual/automatic), and whether the car is air-conditioned, encoded into four letters. The first letter in the Acriss Code represents the general classification of the vehicle (e.g. Mini, Economy, Compact etc.). The second letter specifies the vehicle variant on offer (e.g. 4 Door, Estate, Convertible, SUV etc.). The third letter is generally used to specify the transmission type, although it can also be used to describe how many wheels drive the vehicle, and the fourth letter describes the fuel type and whether the vehicle has air conditioning or not.
Additional classifications based on seat numbers and trunk volume were also set by the Belgian Rent a Car association in order to provide a unified system for assessing the car types in online reservation systems and airline global distribution systems.