Highway locations and various data: speed limits, surface type, access, etc, from the Colorado Department of Transportation (CDOT).

Highway segments and the various quality assurance data along with the overall grade, from the 2018 review of the Colorado Department of Transportation (CDOT).

Road surface treatment planned (estimated) from 2017 through 2020 on highways in Colorado, from the Colorado Department of Transportation (CDOT).

Sign post information: date reviewed, materials used, notes, etc from the Colorado Department of Transportation (CDOT) (links to Sign Locations and Sign Panels).

Traffic counts on highways and various calculations, from Colorado Department of Transportation (CDOT), for 2014

County boundaries and area, from the Colorado Department of Transportation (CDOT) for 64 counties in the state of Colorado.

Traffic counts on highways and various calculations, from Colorado Department of Transportation (CDOT), for 2015

Road surface treatment planned (estimated) from 2015 through 2018 on highways in Colorado, from the Colorado Department of Transportation (CDOT).

Sign panel information: color, image, text, etc from the Colorado Department of Transportation (CDOT) (links to Sign Posts and Sign Locations).

Road attributes including number of lanes, surface type, roughness factor, etc since 1970 from the Colorado Department of Transportation (CDOT).