Colorado Department of Transportation - http://www.dot.state.co.us/ Supervises road construction, maintenance, and weather-related closures, and promotes recreation, tourism, and transportation safety.
E-470 Public Highway Authority - http://www.e-470.com/ Maintains the tolled eastern beltway of Denver which uses the EXpressToll electronic toll collection system. Official site includes toll rates, maps, and an FAQ.
Central City Parkway - http://www.centralcityparkway.com/ Official page of the new facility connecting Interstate 70 and Central City. Site includes maps, background, and FAQ.
Front Range Toll Road - http://www.cololegislativeinfo.com/TollRoad.html Official page on this proposed facility which would run east of Interstate 25. Site includes a map and full text of the related bill.