What factors influence your selection of a safe speed when driving down a long steep downgrade?

The selection of a safe speed when driving down a long steep downgrade is primarily influenced by the total weight of the vehicle and cargo. Heavier vehicles and loads require more time and distance to slow down due to their increased momentum. This means that if you are driving a fully loaded truck, you need to be more cautious about your speed to ensure that you can maintain control and stop safely if needed.

Additionally, the weight affects how the vehicle reacts to braking and the potential for brake overheating, which can lead to brake failure. Therefore, understanding the total weight allows drivers to assess how steep the downgrade is and adjust their speed accordingly to prevent accidents.

Factors such as fuel efficiency, passenger comfort, visibility, vehicle color, and size may play roles in different aspects of driving but are not critical when it comes to maintaining safe speeds on downgrades. They do not provide a direct correlation to the dynamics of vehicle control under varying weight loads on inclines or declines.