In the Hwy sign "9% grade", what does the 9% refer to? how is it determined?

Question

In the Hwy sign "9% grade", what does the 9% refer to? how is it determined?

Answer 1

It means for every 100 feet, the road rises by 9 feet.  It is expressed as a percent (9/100 = 0.09 or 9%)  An inclinometer is I believe what is used to measure this.

Answer 2

A 9% grade means that the road falls or rises, depending on which way you are going, 9 feet for every 100 feet you travel.

Answer 3

9% is the angle of the grade ,thats how that is determined,thats a pretty steep sloop,they start out with a grade of level that is 0% which is level,good luck,and merry x-mas.

Answer 4

a 9% grade......not for me in my trctor trailer hauling 50,ooo lbs of lumber......!     9ft rise(or drop)for every 100ft traveled