Popular rental is a term used to describe a type of business that rents out vehicles, such as cars, trucks, and vans. The most common three-letter acronym for this type of business is CAR, which stands for 'CAR rental.' CAR rental businesses are popular because they provide customers with the convenience of renting a vehicle for a short period of time without having to purchase one. This type of business is especially useful for those who need a vehicle for a short trip or for a special occasion.