The most obvious conceptual question regarding the cab is the difference between the cab-over-engine (also known as cab forward trucks in the US) and the conventional or cab-behind-engine trucks. In the cab-over-engine truck, the driver’s cab is positioned over the engine, and is essentially a cube. In the conventional (cab-behind-engine) design, the engine is covered by a hood and the driver’s cab is built directly behind the engine and its hood.