When driving on grades, which of these is the best choice for a safe speed?

Your vehicle's speed will increase on downgrades because of gravity. Your most important objective is to select and maintain a speed that is not too fast for the:
- total weight of the vehicle and cargo.
- length of the grade.
- steepness of the grade.
- road conditions.
- weather.
If a speed limit is posted, or there is a sign indicating "Maximum Safe Speed," never exceed the speed shown. Also, look for and heed warning signs indicating the length and steepness of the grade. [Commercial Driver Handbook]