Rating the Road: Standardized 4-Wheel Drive Road Rating System

Rating the Road: Standardized 4-Wheel Drive Road Rating System

Page Type Page Type: Article
We are familiar with the usual numerical “class” rating of a climb from 1 to 5, with objective descriptions provided to warrant the various values. Yes, it’s true what may seem to be class 5 to one person may be class 3 to another, and the differences between class 3 and 4, or class 4 and 5, can be extremely subtle. Subjectivity is unavoidable, but with enough experience on hikes and climbs within each numerical heading, we tend to gain a pretty strong feel for properly rating a climb.

The same can’t be said for rating the approach road. Let’s face it: driving to the trailhead is a major variable that needs to be considered. The simple fact is, if you can’t get to the start, your hike or climb may not happen at all (or adds a lot of extra un-planned mileage to the hike). Many reports gloss over the approach road conditions, or offer very broad assessments based entirely on subjective criteria. Some simply report any road as “4-wheel drive” even if it is clear the road hasn’t seen a vehicle in 40 years, or similarly, assume if they bashed their beater Jetta up some old mine road, it’s “2-wd passable”. These subjective ratings are not useful and can be very misleading.

What follows is a rating system, numbered 1-10, established by the Colorado Association of 4wd Clubs. I have seen these ratings used in other books for other states and it seems to have become the de-facto rating system used by 4wd backroad drivers. The intent of this discussion is not to debate the ethics of driving on back-roads, nor is it intended as an off-topic post on the fun and merits of this activity. Back-road and 4-wheel driving is an unavoidable aspect of hiking and climbing – getting there is a necessary condition for the whole adventure, after all!

The ratings are courtesy the CoA4WDCi (their acronym, not mine). It can be found here:

Colorado Association of 4wd Clubs, Inc

The ratings break into three broad categories: 1-4 is “easy” and may allow 2wd passage; 5-7 is moderate and requires 4wd, stock usually okay; 8-10 is difficult to extreme and requires special equipment, experience, and even then, may be impassable. The descriptions below are verbatim from the above website. The photos are mine with some commentary as well. I encourage you to follow up on the above link and all their sub-links; it's good reading and well done.

1. Graded dirt road. Dry, or less than 3" water crossing depth. Gentle grades. 2WD under all conditions except snow. No width problems, two vehicles wide.

Road rating 1 (Kaibab Plateau AZ)

2. Dirt road. Dry, or less than 3" water crossing depth. Some ruts. Slight grades, up to 10 degrees. 2WD under most conditions. Rain or snow may make 4WD necessary. Usually one and a half to two vehicles wide.

Road rating 2 (Blue Peak AZ)

3. Dirt road. Rutted, washes, or gulches. Water crossings up to 6" depth. Passable mud. Grades up to 10 degrees. Small rocks or holes. 4WD recommended but 2WD possible under good conditions and with adequate ground clearance and skill. No width problems for any normal vehicle. Vehicle passing spots frequently available if less than two vehicles wide.

Road rating 3 (Scrub UT)

4. Rutted and/or rocky road. No shelves but rocks to 9". Water crossings usually less than hub deep. Passable mud. Grades moderate, up to 15 degrees. Side hill moderate up to 15 degrees. 4WD under most conditions. No width problems, vehicle passing spots frequently available if less than two vehicles wide.

Road rating 4 (Maple AZ) - Very rocky road, volcanic pumice boulders.

5. Rutted and/or rocky road. No shelves. Rocks up to 12" and water crossings up to 12" with possible currents. Passable mud. Moderate grades to 15 degrees. 6" holes. Side hill to 20 degrees. 4WD required. No width problems.

Road rating 5 (Scrub UT) - It looks okay but this road is steep!!!

6. Quite rocky or deep ruts. Rocks to 12" and frequent. Water crossings may exceed hub depth with strong currents. Shelves to 6". Mud may require checking before proceeding. Moderate grades to 20 degrees. Sidehill may approach 30 degrees. 4WD necessary and second attempts may be required with stock vehicles. Caution may be required with wider vehicles.

Road rating 6 & 7 (Turtle AZ) - The road seen here is very steep, rocky and exposed - probably class 6 by this system. At the bottom is a stream crossing, definitely 12-18" deep, 30 feet across, moderate movement.

7. Rocks frequent and large, 12" and may exceed hub height. Holes frequent or deep (12"). Shelves to 9". Mud 8" deep and may be present on uphill sections. Grades to 25 degrees and sidehill to 30 degrees. Water crossings to 18" and may have strong currents. 1-1/2 vehicles wide. 4WD required. Driver experience helpful.

8. Heavy rock and/or severe ruts. Rocks exceeding hub height frequent. Shelves to 12". Deep mud or uphill mud sections. Steep grades to 25 degrees and can be loose or rocky. Water crossings may exceed 30" in depth. Side hill to 30 degrees. One vehicle wide. Body damage possible. Experience needed. Vehicle Modifications helpful.

9. Severe rock over 15". Frequent deep holes over 15". Shelves over 15". Mud bog conditions (long, deep, no form bottom). Over 30" water crossings with strong currents. Steep grades over 30 degrees. Sidehill over 30 degrees. May not be passable by stock vehicles. Experience essential. Body damage, mechanical breakdown, rollover probable. Extreme caution required.

10. Severe conditions. Extreme caution recommended. Impassable by stock vehicles. Winching required. Trail building necessary. May be impassable. Impassable under anything but ideal conditions. Vehicle damage probable. Personal injury possible. Extreme caution necessary.

(If anyone wants to attach their pictures for examples of roads rated up to 10, feel free to do so. I usually can't or won;t drive anything that severe)

The authors of these ratings stress that these ratings can vary depending on the type of vehicle, whether the vehicle is stock or has special equipment (and what kind), the experience of the driver and the recent weather.

This article is for informative purposes only. I am not suggesting we adopt this wholesale, but it does give some framework within which to judge roads on an objective basis. Even if an author calls a road “4-5”, this is a big improvement over simply saying “passable by 4wd” when it is clearly not, or some other inaccurate over-generalization.

In my reports I have tried to be descriptive about the quality of the roads, and tend (at least I think so) to be conservative as to whether a call a road 4wd, erring on the side of caution. I am one of those people who will use the 4wd option (I have a stock 2001 Nissan Frontier truck) if I think there may be rough stuff ahead, even if the road now is fine by 2wd.

The motivation for this article stems from a hike I did with two others a year ago in Arizona. We were using a very scant personal report from a previous visitor who simply stated “drive the roads to …”, neglecting to mention the roads were pretty rough, steep, remote and involved a large stream crossing. We ended up using more time on the roads than we’d planned.

To each their own. Some of you like not knowing and hoping for the best. Others like to plan accordingly, with at least some idea of what to expect to build that into the overall time framework.


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Viewing: 1-15 of 15
vancouver islander

vancouver islander - Aug 14, 2009 7:01 pm - Voted 10/10

Very useful

You're quite right - we usually go out there with the sole advance knowledge being that an approach is 2WD friendly or you need 4WD with high clearance.

I'll attach a few Vancouver Island approaches as examples. I'd be interested in your opinion of their "grade".

Cheers, Martin


surgent - Aug 17, 2009 2:22 pm - Hasn't voted

Re: Very useful

Hi Martin:

The alder road pic made me smile! Too funny.

I'm no expert at grading, but like many people, have done enough 4wd roads over the years to have at least gained a feel for what's "easy", "moderate" and "insane". Some of those pix could be in the 7 category.

When I think of categories 8, 9 and 10, I picture roads like the ones in Utah that descend off the various plateaus into the canyons, with foot-high shelfs, 20% grades, slick rock and no room for error. My truck wouldn't handle that - or more accurately, the guy driving my truck, usually me, figures the hell with this, I'll walk!



lcarreau - Aug 16, 2009 10:33 am - Voted 10/10

I got a 4WD with high

clearance STUCK on three separate occasions here in Arizona.

The roads can change from year to year, due to precipatation and
flash flooding.

It's always best to bring a sturdy shovel and blocks of wood
with you in case you have to dig yourself out and turn around.


surgent - Aug 17, 2009 2:27 pm - Hasn't voted

Re: I got a 4WD with high

I've been high centered once in California (Whale Peak) and again as a passenger (Weaver Peak, AZ). Arizona's roads have so much clay/caliche in them that when it rains, the roads go to hell and expose rocks, rut like crazy and go from being bad to impassable.

I had an experience in New Mexico coming down from Cookes Peak, driving out the 10 miles or so back to the main highway. The road was mostly flat, but rain made it so slick I had no traction whatsoever! I actually drove most of it by putting my right wheels up on the berms for traction, then inching out wile leaning about 20 degrees to my left.

In Nevada, the soil is much more rocky, which pulverizes well and if graded, can maintain a good tread for a long time. They don't seem to get rutted or as slick as they do in AZ/NM.

I heartily agree: basic extraction devices are a must.


lcarreau - Aug 17, 2009 7:20 pm - Voted 10/10

Re: I got a 4WD with high...

Well Scott:

My hat's off to YOU and the rest of the folks for seeking out the highest/promenance points in the individual states.

I suppose it's always helpful to have a GOOD communication device and full tank of gas when you venture out into them thar hills;
(also a "Plan B or C" if you get stranded & have to wait it out!)

Wishing you the best of luck !!!

Larry of AZ


MoapaPk - Sep 4, 2009 9:32 pm - Voted 10/10

Re: I got a 4WD with high

"In Nevada, the soil is much more rocky, which pulverizes well and if graded, can maintain a good tread for a long time. They don't seem to get rutted or as slick as they do in AZ/NM."

Where in NV? I can show you some roads that may change your mind.


surgent - Sep 8, 2009 10:23 am - Hasn't voted

Re: I got a 4WD with high

I am guilty of overgeneralization. I have been on some pretty bad NV roads too. In very broad, longitudinal terms though, most roads in NV seem to be in better overall shape than those in AZ, at least in my experience. AZ's roads have so much clay in them they turn into mush or rut like crazy after one sprinkling. NV's roads just seem to hang in there better - I am often surprised at how nice they are, even the most remote ones.


MoapaPk - Sep 9, 2009 8:29 pm - Voted 10/10

Re: I got a 4WD with high

Many AZ roads are very muddy for part of the year, but very drivable for the rest. Most of the BLM roads in NV have not been maintained since 2003, and are evolving into terrible shape. Try the roads up Scofield Canyon to Troy, for example. Every DPS report older than 2003 gives overly optimistic conditions.


rayray - Aug 20, 2009 12:08 am - Voted 10/10

Great article!

Good info in this article, Scott. You are right on the mark about road descriptions on many SP pages not telling the whole story. I am probably guilty of this myself....so now I'll have to review the pages that I've posted and fix the ones that need it.


surgent - Aug 21, 2009 3:03 pm - Hasn't voted

Re: Great article!

I noticed you included some photos of the approach roads on some of your reports. A pic is worth a thousand words sometimes!


Dean - Aug 22, 2009 5:58 am - Voted 10/10

So true

The hike is often the easiest part. A good example was Tanks Peak in Colorado last week. My wife was with me and she thought I was going to destroy my truck and leave us stranded on the 4x4 road I chose to get close to the peak on(and she was close to being right). Bob Bolton and I got stuck in the mud in Idaho and had to walk out 20 miles to get help and then there are those "ledge" roads, roads that are barely wide enough for your vehicle with big drop offs and you cannot afford to meet another vehicle coming the other way. One on Pueblo Peak in Oregon is about a mile in length and I was holding my breath both ways.
The list goes on and on. Thanks Scott, you have written a great
article, one that deserves more attention and information that authors of pages need to consider adding, the difficulty of the access roads.


surgent - Aug 25, 2009 3:02 pm - Hasn't voted

Re: So true

I've been fortunate to never (yet) have to hike out 20 miles on a road after getting stuck. Knock on wood. Glad you liked the page.

Sometimes the road is so harrowing getting to the TH that I almost just rush through the hike so I can get back down the bad part of the road before I can enjoy the feeling of success. The road up South Tent Mtn in Utah from the town of Ephraim was so bad - steep, ledgy, parts having slid down the mountainside, then deep ruts from ATVs - that I really couldn't feel comfortable until I had hiked the peak and driven down. It was too much on my mind.


hgrapid - Aug 24, 2009 3:07 pm - Voted 10/10

Excellent - using on my pages

I am presently adding the ratings to my pages.


lcarreau - Aug 28, 2009 11:53 pm - Voted 10/10

Re: I agree, furthermore....

Are you talking about the type of world where you have to remove
yourself from your "comfort zone" to get out and walk the two miles?

I understand the rating system, but I also know that approach
roads can (deteriorate and change) from year to year.


Mountain_girl - Aug 30, 2009 11:45 am - Voted 10/10


Thanks, that's a really cool article. I hope we will all start using a scale when describing access roads. It did happen to me in the past that the road was an absolute nightmare. I am referring to the one in the White Mountains leading to the White Mountain peak. If your car has low suspension, this road is not a good idea :)

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