< Colorado
Special Roads for Colorado
In Colorado, we do not use the dirt road type unless it is for 2 unimproved roads. Any road that a highway vehicle would be able to easily travel would not be considered a "Dirt Road/4x4 trail." See this Forest Service Roads section about Forest Service roads for some clarification. Forest Service.
If the road has been improved at all (meaning that it is a gravel road), we use the street road type. There may be special circumstances, so contact an Area Manager with any questions.
State Highway vs State Route
We do follow the general guidelines here, but in order to have some consistency throughout the state. Colorado uses State Highway (SH-xxx)
See Colorado/Special roads for guidance in Colorado that may not be universal to all other states and territories.