Pneumatic throttle control is a servo system for engine speed control or similar proportional control applications, eg, retarder controls or pump control.

It is used instead of mechanical linkages or cables, especially where long distance or complicated routing between engine and driver’s location is involved, It simplifies the installation when the engine speed has to be controlled from the two or more stations or when the vehicle has a revolving seat.
Typical applications for this system are all kind os off-road vehicles as well as buses, coaches and lorries / trucks.