A method of substantially preventing road speed excursions while traversing a road grade includes: determining, by a controller, a predicted over speed for a vehicle during an upcoming downhill grade based on a difference between a predicted engine braking power of the vehicle and an amount of braking power that substantially prevents a speed of the vehicle from exceeding a speed threshold; and responsive to the determination, controlling, by the controller, one or more components of the vehicle to substantially prevent the vehicle from exceeding the speed threshold.