Detachable all terrain trailer

A self-propelled independently controlled semi-trailer, whereby commercial cargoes can be safely and efficiently transported over roadways and then delivered to off-road sites without first transferring the cargo onto off-road type straight-trucks, comprising:

• (a) a semi-trailer chassis having a plurality of permanently mounted stationary and retractable axles with non-steerable rotatable wheels attached, said wheels positioned at either exterior side of said semi-trailer chassis for enabling said semi-trailer chassis to roll on a surface;
• (b) an engine mounted in said semi-trailer chassis for producing rotational energy;
• (c) a retractable axle, with steerable wheels attached at either end of said retractable axle and located on either exterior side of said semi-trailer chassis, said retractable axle mounted far enough forward to allow it to balance and support said semi-trailer chassis and its cargo once said semi-trailer chassis detached from its pulling truck-tractor and begins its detached mode operation;
• (d) means for controllably coupling rotational energy from said engine to one or more of said permanently mounted, stationary and retractable, steerable and non-steerable, rotatable semi-trailer chassis wheels, during said semi-trailer chassis detached mode operation;
• (e) means for controlling all operations of said semi-trailer chassis in its detached mode operation independently of the operation of its pulling truck-tractor, which includes:
• (i) starting or shutting-off said engine,
• (ii) accelerating/deaccelerating said engine,
• (iii) causing said semi-trailer wheels to rotate at variable speeds in either forward or reverse direction thus propelling said semi-trailer chassis,
• (iv) steering of said steerable wheels,
• (v) braking said rotatable steerable and non-steerable wheels,
• (vi) controlling all functions of any particular cargo body mounted on said semi-trailer chassis.