 Areas with rough terrain or snow usually have squad trucks with four-wheel drive, jake brake, locking differentials, hydraulic brakes, and aggressive tires.Often, squads trucks are old ambulances that have been stripped to carry the necessary tools and equipment needed for an extrication, however, rescue squads or fire departments with a high amount of funding often purchase custom trucks that are more elaborate and functional squad trucks.As such, the size of squad trucks is varying, and can be classified into three distinct categories.