New barrier-protected bike lanes have opened along Chicago's Milwaukee Avenue, the city's most heavily biked corridor.
Thousands of cyclists zip along the roadway each day on commutes into the business district from the northwest.
The section with protective barriers separating the bike lanes from vehicle traffic is along a nearly one-mile stretch just outside downtown.
The Chicago Department of Transportation announced opening of the bike corridor on Thursday. It estimates that bicycles account for more than 40 percent of the traffic along the corridor during rush hour.
Bicycle traffic signals and the city's first bike passing lanes for faster cyclists is part of the roadway.
The city says 20,000 bicyclists commute daily to downtown.
Chicago has 170 miles of bike lanes and aims to reach 645 miles by 2020.