The term 'protective car accessory' can be summarized as a three-letter acronym, BRA. This acronym stands for 'brake retarder assembly, ' which is a device that is installed on the rear axle of a vehicle to help reduce the speed of the vehicle when it is going downhill. The brake retarder assembly works by applying pressure to the rear wheels, slowing the vehicle down and providing additional protection from accidents. It is an important safety feature for vehicles, especially those that are used in mountainous terrain.