Front Range Toll Road
- Official page on this proposed facility which would run east of Interstate 25. Site includes a map and full text of the related bill.
- http://www.cololegislativeinfo.com/TollRoad.html

Central City Parkway
- Official page of the new facility connecting Interstate 70 and Central City. Site includes maps, background, and FAQ.
- http://www.centralcityparkway.com/

E-470 Public Highway Authority
- Maintains the tolled eastern beltway of Denver which uses the EXpressToll electronic toll collection system. Official site includes toll rates, maps, and an FAQ.
- http://www.e-470.com/

Colorado Department of Transportation
- Supervises road construction, maintenance, and weather-related closures, and promotes recreation, tourism, and transportation safety.
- http://www.dot.state.co.us/

The Highways of Colorado
- Contains comprehensive information, including history and essays.
- http://www.mesalek.com/colo/