[P-hack]

I imagine that there would be one controller that manages both motors, possibly a steering angle input as well if you want max efficiency in the corners and curves, though I don't know how you manage traversing a slope (or a crowned road) most efficiently (without the motors fighting each other), off the top of my head. Accelerometers might be better, but they have drift issues, not the fun kind. It may be possible to do it all simply by monitoring the torque(amps) and speed of each motor, but haven't thought it through.