Trail Difficulty Ratings Explained: Green, Blue & Black
TL;DR
- Every place gets a 1-10 score in three bands: Green (1-4), Blue (5-6) and Black (7-10).
- From Blue (5) up, low range is required; from 7 up, expect a rear locker, 33-inch or larger tires and underbody protection.
- There is no national 4x4 rating standard; the BLM says it has none for trail difficulty.
- Utah's statewide OHV signing standard uses a green circle, blue square, black diamond and double black diamond, and rates each segment by its worst part.
- On national forests, maintenance level 2 roads are kept for high-clearance vehicles; levels 3-5 are kept for passenger cars.
The score for each place comes from its own research: an official difficulty rating where a land manager or 4WD club publishes one, plus visitor trip reports. The "basis" line under each place's difficulty section says how that place's number was reached.
1-2/10 · Easy
graded dirt, any high-clearance vehicle
Gear commonly needed
- Stock all-terrain tires
- Standard ground clearance
- No low range required
Hazards to expect
- Occasional washboard or loose gravel
3-4/10 · Moderate
basic 4WD, occasional low range
Gear commonly needed
- 4WD with functioning low range
- All-terrain tires
- Basic recovery board or strap
Hazards to expect
- Short steep grades
- Loose or rutted sections
5-6/10 · Challenging
low range, careful line choice
Gear commonly needed
- 4WD with low range (required)
- A/T or M/T tires, 31"+ recommended
- Rated recovery points front & rear
- Basic recovery kit (strap, shackles)
Hazards to expect
- Off-camber sections
- Loose rock / moderate ruts
- Limited cell coverage possible
7-8/10 · Difficult
lockers / 33"+ tires, body-damage risk
Gear commonly needed
- Locking differential (rear at minimum)
- 33"+ mud-terrain tires
- Rock sliders / underbody protection
- Winch strongly recommended
- Full recovery kit + a spotter
Hazards to expect
- Narrow shelf roads
- Off-camber with exposure
- Body-damage risk from rock contact
- Water crossings of unknown depth
9-10/10 · Extreme
built rigs, winch and spotter likely
Gear commonly needed
- Built rig: lockers front & rear
- 35"+ tires, armor / sliders / bumpers
- Winch (required, not optional)
- Two vehicles / group travel recommended
- Satellite communicator (no cell coverage assumed)
Hazards to expect
- Severe exposure / cliff-edge sections
- High body-damage or rollover risk
- Deep or fast-moving water crossings possible
- Pinstriping / paint damage from brush and rock likely
How We Derive a Place's Score
Where a land manager (BLM, USFS, NPS, a state park) or an established 4WD club publishes its own difficulty rating for a trail, we cite that rating directly and use it as the primary basis for our 1-10 number. Where no official rating exists, we derive the score from published visitor trip reports and the vehicle requirements those reports describe: tire size, whether low range or a locker was needed, and reported body damage or recovery incidents. If neither exists for a place, we mark it "Not rated" rather than inventing a number.
How Official OHV Trail Ratings Work
There is no single national rating system for 4x4 trails. An attachment to BLM Instruction Memorandum 2008-091 says there are no BLM standards for trail difficulty, because driver experience and vehicle capabilities and dimensions vary so much. The same attachment reproduces Utah's statewide OHV trail signing standards, which rate trails on four levels:
| Utah standard | Symbol | How the standard describes it | Closest band on our scale |
|---|---|---|---|
| Easiest | Green circle | Gravel or dirt, relatively flat and wide; gentle curves, shallow stream crossings, minor ruts; no rocks or roots more than 3 inches above the surface | Green (1-4) |
| More Difficult | Blue square | Loose gravel, sand, rock or slickrock; narrow sections, blind turns, steep grades, minor drop-offs; occasional obstacles may strike the frame | Blue (5-6) |
| Most Difficult | Black diamond | Sharp turns, switchbacks, ledges, large rocks, steep side slopes with exposure to drop-offs; low-clearance machines may high-center | Black, Difficult (7-8) |
| Extreme | Double black diamond | Extremely steep and rocky with ledges, boulders and long stretches of loose rock or deep sand; some obstacles will high-center most machines | Black, Extreme (9-10) |
The same standard rates each trail segment, intersection to intersection, by its worst part: a 5-mile Easiest segment with a quarter mile of Most Difficult trail is signed Most Difficult, with caution signs before the hard section.
Forest Road Maintenance Levels
Many Green-band drives follow Forest Service roads, which carry their own official grade. The Forest Service assigns each road a maintenance level (FSH 7709.59, sec. 62.32): level 1 roads are closed and in storage, level 2 roads are maintained for high-clearance vehicles with no warning signs for hazards, and levels 3 to 5 are maintained for a standard passenger car. A level 2 road is roughly the easy end of our Green band; a road the forest doesn't maintain for passenger cars is not a road to attempt in one.
"Can My Rig Do It?"
Every place page compares the band's gear list above with the vehicle you've saved in My Rig (tire size and lift height). It compares two numbers, not your driving experience, your tires' tread pattern or trail conditions on the day. A trail's real difficulty changes with weather, water levels and recent trail damage, so check the season and access notes on the place's own page and confirm current conditions with the land manager before you go.
Recommended gear
A first recovery kit for any 4WD
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Best for a complete strap, shackle and glove kit in one bag.
- Straps, shackles, gloves, damper and a recovery bag in one kit.
- Covers most vehicle-to-vehicle recoveries without buying parts separately.
Best for getting unstuck from sand, mud or snow without another vehicle.
- Nylon recovery boards that give spinning tires grip in sand, mud or snow.
- Double as a shovel to clear sand from in front of the tires.
Best for airing all four tires down to a set pressure at once.
- Automatic deflators preset between 6 and 30 PSI.
- Air all four tires down at once, then stop at the set pressure.
Best for airing back up before you hit pavement.
- Portable 12V compressor rated to 150 PSI.
- Sized for truck and SUV tires.
We research products from manufacturer specs and owner feedback; we don't test them ourselves. How we choose.
Sources
- Bureau of Land Management — IM 2008-091, Attachment 3 (Utah State-Wide OHV Trail Signing Standards) — No BLM trail-difficulty standard; four Utah difficulty levels and symbols; segments rated by their worst part
- US Forest Service — Guidelines for Road Maintenance Levels (2012) — Road maintenance levels 1–5 as defined in FSH 7709.59, sec. 62.32
Trail Ratings FAQ
What does a Green-rated trail mean?
Green covers our 1-4 scores: graded dirt roads (1-2) up through basic 4WD terrain with occasional low-range use (3-4). Stock ground clearance and all-terrain tires suit the easy end; the moderate end calls for working low range and a basic recovery board or strap.
What does a Blue-rated trail mean?
Blue covers scores 5-6: low range is required rather than optional, and the trail includes off-camber sections, loose rock or moderate ruts that reward careful line choice. Rated recovery points front and rear and a basic recovery kit (strap and shackles) belong in the vehicle at this level.
What does a Black-rated trail mean?
Black covers scores 7-10. At 7-8, a rear locker, 33-inch or larger mud-terrain tires and underbody protection are expected and body damage is a real risk; at 9-10 the scale assumes a built rig with front and rear lockers, 35-inch or larger tires, a winch and group travel.
Is this the same scale a land manager uses?
No. It is our own 1-10 scale, built for a quick comparison across every place we cover. The BLM itself says it has no standard for trail difficulty; where a land manager or state program publishes its own rating, such as the green circle, blue square and black diamond symbols in Utah's statewide OHV signing standard, the place's difficulty section cites it.