Special Roads for Colorado
Colorado uses the "unpaved" road attribute when the road is "dirt" or "gravel" but is maintained or "improved" by the city or county. This means that road is graded and leveled from time to time. The "Off-Road/Not Maintained" road type will be used for "2 track" jeep trail type unimproved roads. These type of roads are normally found in the mountain areas of the state and should rarely be used around or in any city environment. If you can't decide on what type to use just think, if a typical highway vehicle could easily travel (at 10 - 25 mph) should be considered a "street" with the "Unpaved" road attribute.
See this Forest Service Roads section about Forest Service roads for some clarification.
You may ask "Why use "Unpaved" or "Off-Road/Not Maintained" at all?" Well, using Unpaved on a Street road type adds a Time penalty to those segments of road and using Off-Road adds a larger Time penalty. The Time penalty is used by the routing server to determine the fastest route and a Dirt road, no matter how improved, will never be as fast as Paved. But then why not use Off Road for all dirt? In the app, there is a setting to Avoid Dirt. This can be set to just small lengths of Off Road or avoid them altogether. If we made the Unpaved roads all Off Road then 60% of all roads in the state would be avoided by the app and may give users very long routes where the Unpaved road would have saved hours of time.
As always, there may be special circumstances. If you feel you have a special circumstance please contact the State Manager or an Area Manager with any questions.