Abstract: A vehicle guidance system includes a computer for generating signals to control a number of vehicles to carry out movements within a predetermined area. Data identifying locations of notional points on the floor of the area are entered into the computer together with a look-up table specifying pairs of those points between which movements of vehicles may be required, and specifying which other of the movements between pairs of points must be considered as potential causes of collision between vehicles when any particular movement is to be effected. When a vehicle movement is requested, the computer determines from the table which other movements must be considered, and determines whether any such movements are being effected at that instant. If so, the computer inhibits the requested vehicle movement or, if not, it initiates the requested vehicle movement.