A system 10 for controlling operation of a vehicle 12 in a defined area 14 includes a perimeter 16 defining a boundary of the defined area 14. A user interface 18 is provided for at least one of controlling and monitoring movement of the vehicle 12 as it traverses the area 14 and monitoring the location of the vehicle 12 relative to the perimeter 16. The system 10 further includes a controller 26 to which the vehicle 12 is responsive, the vehicle 12 having a plurality of modes of operation, one of which is an autonomous mode and another of which is an operator controlled mode. The controller 26 is operative, when the vehicle 12 is operating in the autonomous mode and the vehicle comes within a predetermined range of the perimeter, to inhibit the vehicle 12 from crossing the perimeter 16 and, when the vehicle 12 is operating in the operator controlled mode or is converted from autonomous mode to operator controlled mode, to permit the vehicle 12 to cross the perimeter 16 under control of the operator.