A system is provided for controlling the speed of a vehicle having a power
plant and a transmission. A control unit is configured to receive a
signal indicative of the speed of the vehicle. The control unit is
further configured to determine a desired output speed of the power plant
based on the signal indicative of the speed of the vehicle, a signal
indicative of the gear ratio of the transmission, and a desired vehicle
speed associated with the gear ratio. The control unit is also configured
to send a signal to the power plant, such that power plant operates at an
output speed that substantially maintains the desired vehicle speed in a
manner substantially independent of a magnitude of load on the power
plant.