Arkansas Commercial Driver License (CDL) Practice Test

The most appropriate action to take before starting downhill is to downshift. Downshifting to a lower gear helps to control the vehicle's speed without relying solely on the brakes, which can overheat and lead to brake failure. By downshifting, you engage the engine's compression to assist in slowing the vehicle, allowing for safer and more controlled descent on a decline. The other options may not contribute effectively to safety when heading downhill. Increasing speed is risky and can lead to loss of control. Tapping the horn might alert others but does not address the vehicle's handling. Flashing lights from low to high is unnecessary and may not effectively communicate your intentions to others on the road. Therefore, the safest and most effective action is to downshift before heading downhill.