A road speed control system for a vehicle driven by an internal combustion engine includes a control computer operable to control engine fueling based on inputs from at least an accelerator pedal position sensor, a vehicle speed signal, and at least one control signal. According to one aspect of the invention, the control computer is responsive to a first control signal to decrease the maximum road speed limit value and to a second control signal to increase the maximum road speed value, to thereby provide a road speed limiting system operable under manual engine fueling conditions. According to another aspect of the invention, the control computer is responsive to at least one control signal to activate a maximum road speed limit override feature for temporarily increasing the maximum road speed limit value to, for example, facilitate passing attempts.