Driveway: How steep is too steep?

So SWMBO and I have been exploring land to buy in the mountains of WV and VA over the past few years, and one common issue that comes up is the frontage to the road is generally very steep to get up to a more level spot.

The intention for this property is to slowly build a cabin, then shop, then house, so we need the ability to get at least a dumptruck/Cement truck type load on site.  Driveway is notionally gravel, could be paved if it helps.

Is there a good rule of thumb for "yeah, that ain't gonna work"?

Yesterday's example checked every box we had except for this, and the 'easiest' entry point was a short 200' section that rose about 80'.  So ~22 degrees or 40% grade.

What say the hive?  

I had a friend or parked his old civic on his driveway which was probably 30% and it spun a rod bearing.

As someone who lives in the snowbelt,   I can't fathom driveways over 10-15% grade

The steepest grade allowed on highways is 6% in nearly all cases.

Also, think about deliveries, etc.  Most trucks aren't even going to try something steeper than about 20%, even over a short distance.

I would avoid anything steeper than about 15%.

We went through the same issues 2 years ago. One of our criteria was being able to get a motorhome down the driveway. We ended up with a farm with a fairly steep driveway and a bridge. The slope is about 20-25%. We did a fair amount of research on the bridge and vehicle access before we bought it. Getting my motorhome up or down and across the bridge is challenging but possible.

Worse is getting any 2WD vehicle up it. If you don't get a running start or have to stop at the top, you have to back down to the bottom and try again. Our drive is only 80'. 

You also need to consider the breakover and approach/departure angles for any large vehicles. I did some careful measuring before I attempted ours with the motorhome.

A couple of thoughts. Do you have a 4WD vehicle? A little rain or snow could keep you from going or leaving. Can you afford to pave the driveway? If not you are dealing with gravel and it is going to need repairs as rain and traffic move the rock to the bottom of the slope. Do you have a way to repair the driveway? We have to move the gravel back up the drive as the rain and vehicles push it to the bottom. Luckily we have a tractor with a loader to do it.

Really crappy iPhone video of my motorhome climbing the driveway. 

Duke said:

The steepest grade allowed on highways is 6% in nearly all cases.

Came here to pretty much say this. I subscribe to a city planner on YouTube who plays city planning games, and one thing he always struggles with is keeping road grades in check.

Does it snow there?

When my parents moved to remote New Mexico, they had to use a tractor to pull the moving van (box truck) up the driveway.

UPS and FedEx delivery vans don't have any trouble with the grade though.  Makes me wonder if they have published constraints on deliveries.

I don't know about WV but a quick look at NC shows no requirements for driveway grades. Apparently, some of them can exceed 30%. 

NC does have a maximum grade for subdivision roads of 18%.

The maximum recommended grade for a gravel driveway is 14%. Anything more than that has stability issues. This is why we have to work on ours every 6-8 months.  

Too steep:

I don't know the grade of it, but our driveway growing up was pretty damn steep. At least 15%. But just about anything could get up it because of the low entry and gradual increase in grade to the main part. Salt and self propelled snow throwers are your friend. 
 

When you park, brake, parking brake, then in park or gear. When you leave, foot on brake, put it in gear, release parking brake. 
 

If you don't use the parking brake regularly you'll want to make sure it is lubed. 

Thanks for the responses!

The situation would be very much like the inverse of Toyman's run up to the road.  The cars would be parked on level ground, but would need to transit a short but significant climb to get there.

My current suburban driveway has a section at the beginning of it that's 15-20% grade, and it's a challenge for some delivery drivers to make the transition without scraping.  To assist with this, we just put a deliveries box at the curb. UPS and FedEx use it well, however Bezos' robot overlords don't recognize this as valid GPS coordinates. This has yet to be an issue with any of my vehicles or any dump trucks we've had drop off.

So my WAG for this situation was that double my current driveway (40%) was too much, but a bit more (25%, 30%?) may be achievable.

My experience is having the driveway going "up" from the road is much easier to deal with than "down" from the road.  You're going downhill when you leave and probably have better site lines to on coming traffic. Also the road doesn't use your driveway as a drainage path. Yes, pave it.

Gearheadotaku (Forum Supporter) said:

My experience is having the driveway going "up" from the road is much easier to deal with than "down" from the road.  You're going downhill when you leave and probably have better site lines to on coming traffic. Also the road doesn't use your driveway as a drainage path. Yes, pave it.

This. My driveway (paved) is downhill from the road. It is challenging in non-4WD/AWD vehicles when it snows. And yes, it acts like a drain. My across the street neighbors have steep, uphill, gravel driveways. Tonight I'll be cleaning up all of their gravel from yesterday's storms. 

This thread made me curious as to the slope of our driveway, because I would absolutely never waant anything steeper in any environ that includes winter weather.  With my handy angle tool, it looks to be about 18-20% and 150' long on the sustained steep.  I have no idea as to what you're planning, but I can say from experience that my driveway SUCKS, haha.  Impossible to clear in the winter, and water runs off of it so quickly that we have to re-trench the sides of the driveway after any major storm.  Most utility vehicles now know better and just deliver from the roadside.  

Is there any way to sort of 'bench cut' a driveway in on a diagonal?  It might be all you need to get it manageable...

Here is the AI Copilot answer:

The maximum driveway slope varies depending on location and local regulations. Generally, residential driveways fall between 10% and 18%, with 15% or higher considered very steep. Some areas allow up to 20%, but it’s essential to check your municipality’s guidelines.

So I'm thinking 40% is probably no bueno.

If I can't get my lowered BRZ up it without scraping the nose, it's too steep. I had my '15 BRZ (also was lowered) when I bought this house and that was definitely a determining factor when looking at homes.  

Of course, I still pull into the driveway slowly and at an angle, but haven't had an issue. 

stuart in mn said:

Too steep:

"Arrange a viewing of your future home in King-of-Hammers Heights today!"

In reply to GameboyRMH :

An idea: just replace that driveway with a quarter pipe. 

I did some work in rural WV. EVERYTHING was really steep. I doubt there are any guidelines at all.
 

Truck drivers who work in those areas are used to it. You'd be shocked at what they can do. Concrete trucks are 6WD.  It's also always possible to hire a concrete pump truck. 
 

Doesn't make it ok...

My north facing driveway is over 15% and paved.  I've kept up on snow removal, but sometimes it's packed or icy.  Over the 26 years I've lived here every vehicle I've parked outside has slid out of the driveway at least once... including theSuburban.  The prize went to the Neon, which slid down the drive, across the road, and into the park.

At least make a radius at the top so a sports car can get in!