Final answer:
The factors that determine the selection of a "safe" speed when driving down a long steep downgrade include the steepness of the slope, the length of the downgrade, the condition of the road, the weight and condition of the vehicle, and the presence of other vehicles or obstacles.
Step-by-step explanation:
The factors that determine the selection of a "safe" speed when driving down a long steep downgrade include:
- The steepness or gradient of the slope: A steeper slope requires a slower speed to maintain control of the vehicle.
- The length of the downgrade: The longer the downgrade, the more time you have to slow down and regulate your speed.
- The condition of the road: Factors such as the presence of ice, gravel, or wet surfaces can affect traction and require lower speeds.
- The weight and condition of the vehicle: Heavier vehicles require more time to slow down and may have reduced brake efficiency.
- The presence of other vehicles, pedestrians, or obstacles: The need to navigate around or avoid obstacles may require slower speeds.