Guard / wall height at surface parking lot?

[palikona]

I’m designing a multi family project with a surface parking lot. There is a steep drop off at the end of the lot, so I’m researching how high of a guard or wall I need in order to prevent cars from accidentally driving off the end (or people for that matter!)
Per IRC, would the guard need to be 30” high above the parking lot surface? And would I ask the structural engineer to design the wall so it can take the impact of a car driving into at a slow speed? Or should it be a guardrail like you’d see on a highway (or something similar but more attractive)?
Thank you!

 

[Yankee Chronicler]

If you are regarding the guard as protection for a walking surface adjacent to the drop-off, under the IRC the guard height should be 36 inches above the walking surface.

If it's only to prevent vehicles from driving into the abyss, that's not covered by the building code. I would look to AASHTO standards for guide rails, and I would require it to be designed by a qualified civil engineer. Not a "structural" engineer who designs buildings for a living -- a civil engineer, who designs roads and bridges for a living.

Note that you used an incorrect term when you referred to "a guardrail like you’d see on a highway." Those Bethlehem wavy steel rails we see along the side of roads everywhere are NOT "guard" rails -- they are GUIDE rails. Their purpose is not to stop a vehicle that drives straight (or nearly straight) into the barrier. They are called "guide" rails because their purpose is to catch a vehicle that has strayed out of the traffic lane and redirect the vehicle to (more or less) follow the roadway.

Guide Rails Available in Pittsburgh, PA from Bethlehem Wire & Fence Co.

Yes, vehicles do occasionally hit Bethlehem guide rails head-on or nearly so. When that happens, there's a good possibility that the vehicle will go right through. I have seen multiple wrecks where that occurred.

https://www.nj.gov/transportation/eng/documents/BDC/pdf/BDC10MR01Attachment.pdf

https://www.dot.ny.gov/divisions/engineering/design/dqab/hdm/chapter-10

 

[e hilton]

Guardrail would work for cars … what about people? You’re in Colo … would a guardrail be better than a wall with the open space below so snow could be plowed off the end?