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.