Karosa ŠD 11 is completely different from its predecessor, Škoda 706 RTO-LUX, which had engine in front and two doors.

ŠM 11 is model of Karosa Š series.

It is derived from Karosa ŠM 11 city bus, and also unified with intercity bus Karosa ŠL 11.

Body is semi-self-supporting with frame and engine with manual gearbox in the middle, between the wheels.

Driver's cab is not separated from the rest of the vehicle.