What is the safest way to control the speed of a motor vehicle on a long downhill road?

The safest way to control the vehicle speed on a long downhill section is to use the engine to brake, lower the transmission gear, reduce the engine speed, do not step on the accelerator, and make full use of the engine's braking response to effectively reduce the speed of the vehicle. Braking frequency to prevent brake pads from being too hot and causing failure due to prolonged braking.

When driving a motor vehicle down a long slope or continuously downhill, the vehicle speed will become faster and faster. If the service brake is used continuously, when the brake temperature rises to a certain level, the braking effect will drop sharply. The best way to control vehicle speed is to drive in a low gear and make full use of engine braking to slow down.

Precautions when driving down a long slope:

1. Reduce the speed before going down the slope so that the vehicle enters the downhill slope at a slow speed.

2. Shift into the appropriate gear before going downhill. Generally, second or third gear should be selected. It is strictly prohibited to change gears after entering a downhill section.

3. It is strictly forbidden to coast in neutral on downhill sections. You must engage in an appropriate gear and use the restraint of the engine to reduce the speed of the vehicle.

4. Before going downhill, you should test whether the braking performance is good. If there is a fault, you should eliminate the fault before going downhill. Use the brake with caution on the downhill section.

5. Do not turn the steering wheel hard on the downhill section, because the inertia of the downhill section is large, the speed is high and the steering wheel is improperly used, which can easily cause the car to roll over.