Question When traveling down a downgrade, the speed of a vehicle will likely: Answers Decrease. Stay the same. Increase. Explanation The force of gravity will cause a vehicle's speed to increase when traveling downhill. This questions appears in the following tests: Alabama Class B Knowledge Test Arizona Class B Knowledge Test Hawaii Class B Knowledge Test Maine Passenger Michigan Class A Knowledge Test Michigan Class A Knowledge Test Montana Class A Knowledge Test Montana Class A Knowledge Test Nebraska Double New Mexico Tank North Carolina Class A Knowledge Test Oklahoma Tank South Carolina Class A Knowledge Test