Preliminary Driveway Layout Grade

[AAART]

I am doing a private site-plan driveway layout. The required rise is 40ft. What is the maximun grade to use for planning.
The site is in Wisconsin and will be paved but require winter snow plowing.

 

[RWF7437]

Some typical numbers:

Freeways: max 6 % grade

City Streets: max 10% to 15%

Boat Ramps usually 12%-15%

With 40 feet of rise in snow country this could be a very long driveway or park at the bottom in Winter.

 

[gibfrog]

I would venture to guess 20%-40%. However, you could contact
Robert Fasick
Wisconsin DOT
Bureau of Highway Operations
P.O. Box 7986
Madison, WI 53707-7986
(608)266-3438
robert.fasick@dot.state.wi.us
or contack your local city.county engineer.

Ask him what are the maximum reccomended grades for a driveway connection. You also will need to construct vertical curves to deal with the slope transitions and not bottom out. The Wisconson DOT will also have this data. The question is can you understand it enough to properly apply it.

Now, do yourself a favor and hire a local Civil PE to design your driveway. You may need switch backs and other items of concern like sub surface conditions, soil compaction, base materials, asphalt thickness, etc... I know better than to try to design something beyond my competance. Your desire to learn about other engineering disciplines is to be commended.

Clifford H Laubstein
FL PE 58662