A powertrain controller for a vehicle comprises a vehicle load estimation module, an adaptive power demand module, a throttle map module, and a transmission gearshift map module. The adaptive power demand module selects one of N mappings from pedal position to power demand based upon a vehicle load index and determines a power demand signal based upon a received pedal position signal and the selected one of the N mappings. The throttle map module selects one of P mappings from speed to throttle control based upon the power demand signal and determines a throttle control signal based upon a received speed signal and the selected one of the P mappings. The transmission gearshift map module selects one of Q mappings from vehicle speed to gear selection based upon the power demand signal and determines a gear control signal based upon a received vehicle speed signal and the selected one of the Q mappings.