This system is used by the Northern California chapter of TTORA.
|1-3||1-3||These trails can usually be navigated by a 2WD vehicle. Rain or snow may require the use of 4WD. Minor obstacles including ruts and small rocks may be encountered. Water crossings are shallow.|
|4-6||4-6||Four wheel drive is required for many sections of these trails. Lockers are helpful. High clearance is a plus for navigating obstacles including boulders, moderately deep water crossings, and deep ruts. Sections of the trail may be steep or off-camber. Rock sliders and high-clearance bumpers will go a long way to prevent body damage.|
|7-9||7-9||Four wheel drive is required for most sections of these trails. Lockers are recommended. Larger tires and low gears are highly recommended. Many sections of the trail will be steep or off-camber. Rock sliders and high-clearance bumpers are highly recommended. Not recommended for inexperienced drivers.|
|10||10||10 rated trails are extreme. Large tires, two lockers, and low gears highly recommended. Obstacles may include extremely off-camber spots, large boulders, and steep difficult hillclimbs. Body damage and parts breakage is likely for all but the most prepared and skilled drivers.|
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.