A cab for a highway truck or tractor is disclosed in which a sleeping compartment including a sleeper bunk assembly is located between a ceiling of the driver''s compartment and the roof of the cab. A bunk assembly for highway vehicles is disclosed including frame members connected to the vehicle by resilient support structures for enabling relative movement of the bunk vertically with respect to the vehicle and thereby dampening vertical shock loads. A mattress-supporting pallet extends between the frame members and second support structures are located between the pallet and the frame. These support structures enable motion of the pallet in forward and rearward directions in the vehicle so that shock loads from pitching are minimized.