Anybody have a unique steep driveway with ideas?

Even Sam was tired walking up.
 

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I need to hack away at this switchback idea with some simple logic and napkin math:

My 2015 Colorado has a pretty decent turning circle of 41 feet for its wheelbase, which I looked up because it turns pretty tight for a truck. A new-ish Wrangler is somewhere between 35 and 40 feet if I remember correctly. Let's say 40 feet and assume that many/most vehicles of any size can't actually turn that tightly.

Why we call it "turning radius" in this country I don't know. "Turning radius" is actually the diameter of the circle, not the radius of the circle, which is why everyone else in the world says "turning circle" instead. So I'm saying "turning circle". /rant

So you've got a 40 foot diameter circle, so a half circle with a 20 foot radius for each side of the property if you're doing a switchback. You've got less than 10 feet of straight connecting them if you don't touch the property line (because the property is 50 feet wide), and even less if you make the switchbacks large enough that a non-Jeep can drive up the driveway.

So you're stuck with moving the 20 foot radius half-circles apart, staggering them up the hill so they aren't as close to overlapping. Just like the street in SanFran on the previous page. By the time you space them apart enough to fit them on a narrow 50 foot wide piece of property, you're largely driving straight up the hill again. Might be a bit of improvement, depending on the angle of the sections between the turns.

So you'd end up with a snaking driveway, but not really any proper switchbacks.
 
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6BangBronk said:
A standard cross section of a parking lot with straight lined parking on both sides with a 2 way center drive isle is about 51' wide
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58-60 ft for perpendicular parking with two way traffic. :flipoff2:
 
I don't have anything except a big azz bungee cord would be useful for descents on a straight shot :lol: ...........w a deep cut @ the top you could less the slope a bit. You really need to topo it and then you can play w grades/designs and maybe find a reasonable solution. I would rather have sweeping switchbacks and some strategic guardrails for safety as opposed to a straight run.
 
RatLabGuy said:
This is gonna be really fun when it snows.
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A stationary winch and a guide track (so you don't slide off of the crown into the ditch) would be fun, but not practical. I don't even want to think about the kinetic energy stored in 4-500 feet of winch cable under tension...That could hurt.


No, wait... Rocket sled!!!!!
 
Maybe just a straight shot up the side with some runaway exit ramps like you see on the interstate but much smaller scale to the other side for the way down.
 
Seems like you could cut down the top and extend the run to get that number down. I'd shoot for 30-32% for a max slope. That's still very steep, and I dunno WTF you do in the snow/ice, but it would be driveable the rest of the time. Switchbacks will "help", but given the fixed width, I'm not sure they make enough difference to matter. It might be one way to get the grade down on the last 100ft, though. Sweep to the high side of the hill on a more gentle section, then sweep to the low side of the hill on a steep portion to extend the run and decrease the rise. You're basically using it as a means to shift grade from the steepest portions to areas that are less steep.
 
Holy... crap... I want one of those... Can you tow a mower deck with it?

I did some simple math, and it works out to be average 32% grade if you assume a straight slope (470 long, 150 high), 17.7 degrees. Switchbacks may get you down to around 23% grade on the straights (13 degrees with 9 switchbacks at 40 foot circle, measured in the center of a 10 foot wide driveway), but you'd have 9 switchbacks over that distance. I made a quick CAD model to check. I put the left hand switchbacks staggered 105 feet apart, and the right hand 105 feet apart too for 9 total.

If you do 10 switchbacks on a 90 foot stagger, it would be 19.5-20% grade roughly. I'm sure I'd be sea sick by the time I got to the top.

Seeing it in CAD as a wedge, it's an incredibly long strip of land for the 50 foot width. It looks like a very narrow doorstop.
 
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Fabrik8 said:
Holy... crap... I want one of those... Can you tow a mower deck with it?

I did some simple math, and it works out to be average 32% grade if you assume a straight slope (470 long, 150 high), 17.7 degrees. Switchbacks may get you down to around 23% grade on the straights (13 degrees with 9 switchbacks at 40 foot circle, measured in the center of a 10 foot wide driveway), but you'd have 9 switchbacks over that distance. I made a quick CAD model to check. I put the left hand switchbacks staggered 105 feet apart, and the right hand 105 feet apart too for 9 total.

If you do 10 switchbacks on a 90 foot stagger, it would be 19.5-20% grade roughly. I'm sure I'd be sea sick by the time I got to the top.

Seeing it in CAD as a wedge, it's an incredibly long strip of land for the 50 foot width. It looks like a very narrow doorstop.
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This is tremendously worthy preliminary information. I plan on doing a grading plan to calc side slopes / retaining walls if necessary (hopefully not). And running a turning radius program just to see what wheel base it says can go up. I will use this to get me started. Sounds like enough thought process to run with it though. Thanks Fabrik8!!! You da man!
 
I'm an MechE and not a CivE, so take everything with a grain of salt. I know nothing about actually building roads or the practical considerations. Vehicle dynamics, yes. Roads, no.

It really would look like that street in SanFran on the first page. Tight switchbacks with very little straight to string them together, and the original grade is probably about the same as what you have.

Yep, Lombard street. There's your driveway if you go that route. Apparently it was 27% grade and is 600 feet long. So it looks like I'm overestimating the number of switchbacks you'd probably need, because it only has 8 but is 600 feet long instead of your 500 feet. It looks wider though based on the size of the cars, so it could have less switchbacks for the same length.

aupload.wikimedia.org_wikipedia_commons_c_c6_Lombard_Street_San_Francisco.jpg
 
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I think your really over thinking the whole thing. 30ish degrees isn't horrible for the mountains ( not great but ive seen much worse). If your really worried about the grade do as Shawn said cut the top fill the bottom. Grade it, gravel it and put in good drains in. There isn't going to be a ton of traffic on it so once its all packed down it should do well. As long as you keep a steady slow pace down it, it shouldn't wash board to bad. I drove a 2wheel drive ranger up a drive way steeper than that for years without much problems. Depending on the county your in depends on the amount of snow you will get, but on an average year I'd say less than 20 days a year you wouldn't be able to get up and down it. Get a 4wheeler with a snow plow and plow it before it gets deep and you'll have even less days you can't drive up it.
 
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