How steep can a driveway be?

I'm in a hilly area, and one of my driveways is STEEP. I measured it today at a little over 16 degree, or a little over 28% grade. When I backed down the drive a few days ago, I was concerned about the braking power. I had to press the brakes pretty hard. That drive will not work for us in the future, especially if there is any moisture on it.

I plan to build a barn with a new driveway very soon. I've done a few searches on the site and cannot find any threads on this. In addition to watching the transition angle, does anyone know the recommended maximum angle for a Prevost going up or down hills? I know it will pull the 28% grade, but the braking concerns me more. My front tires slid a little as it was.

This will affect where I put the new driveway. It will be expensive, but so was the bus!

For extreme driveway 101, contact Jon on PC, he has the steepest driveway known to man.

I remember putting my coach on a ship in Alaska at low tide and that ramp was at least that steep. Yes, it took a lot of pedal pressure to keep it from rolling. The ramp was so steep that the crew had to adjust the ramp for both the front and rear overhangs to clear.

I would not be too concerned with the angle even though it may seem scary. I'd be more concerned with the how that would affect the transmission.