Over the next two weeks, Next City will unroll short profiles of 77 people, places and ideas that have changed cities this year. Together, they make up our 2012 Disruption Index. Forefront subscribers can download the Index in full as a PDF, complete with beautiful designs and graphics by Danni Sinisi. Readers who make a $75 donation to Next City will have a full-color printed copy of the Index mailed to them.

Within just the first few weeks of taking office in May 2011, Chicago’s new transportation commissioner, Gabe Klein, was already letting his inner cyclist shine. He opened the first section of protected bikeway in the city, part of 100 miles promised to be installed within the first term of his new boss, Mayor Rahm Emanuel. The quickness of this bike lane’s installation is indicative not only of Klein’s early career in the bike business, but also of where his priorities will lie as he guides transportation policy in the city.

Klein, who previously served as the head of transportation in Washington, D.C., has already been instrumental in shifting Chicago’s transportation diet away from cars and toward walking, cycling and transit. He has pushed an ambitious 10-year plan to end all road fatalities in the city, released the city’s first-ever pedestrian plan in September, and been at the front of a push to add bus rapid transit service to the city’s already extensive transit network.

That this is only Klein’s second job in government in his now four-year career as a bureaucrat makes his accomplishments so far somewhat surprising. Or, alternatively, this outsider’s perspective may be the best way to explain his success.

Nate Berg is a writer and journalist covering cities, architecture and urban planning. Nate’s work has been published in a wide variety of publications, including the New York Times, NPR, Wired, Metropolis, Fast Company, Dwell, Architect, the Christian Science Monitor, LA Weekly and many others. He is a former staff writer at The Atlantic Cities and was previously an assistant editor at Planetizen.