Wednesday, November 02, 2011

Road Rating System

The following Road Rating system is used on this blog.  It roughly parallels the climbing world's Yosemite Decimal System.

Class 1: Corvette. Paved or very good graded dirt or gravel roads. Suitable for any highway-legal vehicle.

Class 2: Toyota Camry. Gravel or dirt road with some rocks, bumps and/or washboard.  Suitable for any normal-clearance passenger vehicle.

Class 3: Subaru Forester.  Rough gravel, dirt or rock road with bumps, steps or water crossing that make it challenging for typical passenger cars, and better suited for light-duty SUVs with at least medium ground clearance.

Class 4: 4WD Pickup or SUV. Very rough or otherwise challenging rock or dirt road typically requiring one or more of the following: 4WD, high clearance, off-road tires, slow speed and basic off-road driving skills.  May include deep ruts, high steps, cambered roadways, large loose rocks, and/or significant water crossings.

Class 5: "Wheeling" Jeep, etc. Class 5 can be broken out into subclasses: 5.1, 5.2, 5.3 and so on.  All Class 5 roads are suitable for high-clearance, 4WD vehicles with off-road tires.  Driving with lesser equipped vehicles may be possible, but damage to the vehicle is much more likely, and off-road driving skill and road-building skills are likely to be required.

There are several factors that make a road challenging.  Where one of these is a major contributor to a road rating, it is listed after the class rating.

  • Loose rocks
  • Rock steps
  • Mud (includes slippery clay)
  • Ruts
  • Sand
  • Steep (climbs or descents)
  • Exposure (as in rock climbing, exposure to what appears to be a long drop)
  • Water crossing
  • Obstacles (e.g. fallen logs)

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