Unpaved Roads
We generally discourage establishing speed zones on unpaved roads. In doing so, drivers establish expectations that the road is safe to drive at the posted speed. Conditions of unpaved roadways change drastically depending on weather, season, traffic volumes and degree of roadway maintenance. Establishing the appropriate speed limit for all conditions is difficult, if not impossible, particularly when the roadway condition may change rapidly.
Considering the changing roadway conditions and other factors listed in OAR 734-020-0017, ODOT only establishes speed zones for unpaved roads that are gravel.
OAR 734-020-0017 details ODOT's criteria for unpaved public roads. The road authority must make a request to the state traffic-roadway engineer requesting delegated authority to perform a speed zone investigation on an unpaved gravel road under their jurisdiction. ODOT will only grant permission for individual gravel roads; we do not grant blanket authority. The road authority must make the request on a case by case basis. Report requirements and the delegation process are detailed in the Oregon Speed Zone Manual.
Speed Zone Investigation Data and Templates