This is the system used by the Yuma 4 Wheelers.
|EASY||1-3||Features trails with obstacles that are easy to navigate. In optimum weather conditions, these trails may not require the continual use of 4-wheel drive. These roads are occasionally graded or maintained. They may cross sandy washes and sections may be rough (washboards).|
|MODERATE||4-6||Moderately demanding trails on which 4-wheel drive will be needed, as well as some driving skill. You may encounter a wide variety of challenges (Potholes, minor washouts, medium size rocks, and mud holes) on these trails. Higher ground clearance and Off-Road tires are recommended. 31" or larger tires recommended, but not essential. Body damage is unlikely, but possible. "Arizona Pinstripes" are very possible. In some cases a "M" rated trail may be easier for a smaller truck, but harder for a larger truck.|
|DIFFICULT||7-8||These trails traverse very rugged and/or steep and dangerous terrain, low-range 4-wheel drive is required. Higher than stock ground clearance is required. Aggressive tread and low air pressure are required. Traction Devices (Lockers or limited-slip) in the differentials (front and rear), lift, and larger tires are highly recommended. These trails require above average Off-Road driving skills. High-Lift jacks and winches would also be helpful. There will likely be paint damage and possible vehicle body and/or mechanical damage.|
|EXTREMELY DIFFICULT||9-10||These trails are for the hardcore 4-wheeler only. These trails require highly modified vehicles, including lifts, excellent articulation, lockers front and rear, 33" tires or larger with aggressive tread, winches, high lift jacks. A High level of Off-Road driving skill is required. Paint, body and/or mechanical damage is very likely. Rollovers will be more common on these trails and a winch may be used on at least one obstacle.|
Note: Trail ratings are highly subjective. A trail that is easy for an experienced driver with a highly modified vehicle may be impassable for a novice driver in a stock vehicle. Weather conditions may also significantly affect the difficulty of a trail. Also, the difficulty of a trail may change over time, as trail use, weather, and maintenance modify the trail. Always check with the managing organization and/or recent users before planning a trip on a trail and scout ahead on foot if you are not sure of current conditions.