A highway expansion and transit project for the southern I-25 corridor, dubbed T-REX (Transportation Expansion Project), was completed on November 17, 2006. The project installed wider and additional highway lanes, and improved highway access and drainage. The project also includes a light rail line that traverses from downtown to the south end of the metro area at Lincoln Avenue. The project spanned almost 19 miles (31 km) along the highway with an additional line traveling parallel to part of I-225, stopping just short of Parker Road.
The League of American Bicyclists has rated Colorado as the sixth most bicycle-friendly state in the nation for the year 2014. This is due in large part to Front Range cities like Boulder, Fort Collins and Denver placing an emphasis on legislation, programs and infrastructure developments that promote cycling as a mode of transportation. Walk score has rated Denver as the third most bicycle-friendly large city in the United States. According to data from the 2011 American Community Survey, Denver ranks 6th among US cities with populations over 400,000 in terms of the percentage of workers who commute by bicycle at 2.2% of commuters. B-Cycle – Denver's citywide bicycle sharing program – was the largest in the United States at the time of its launch, boasting 400 bicycles. Through the acquisition of new grants, the program has expanded each year, adding dozens of new stations, hundreds of bikes, and by beginning service during the winter months.