The Brian Lehrer Show Edit this Published in The Brian Lehrer Show Bike Messengers and the City Listen 14 min Queue Download this audio Want to embed this player? Use the code below. More info. <iframe width="600" height="130" frameborder="0" scrolling="no" src="//www.wnyc.org/widgets/ondemand_player/wnyc/#file=json/151862"></iframe> Share on Facebook Share on Twitter Email a Friend Urban bike messengers are a devoted bunch with their own subculture. Jeffrey L. Kidder, assistant professor of sociology at Northern Illinois University and a former bike messenger, discusses his new book Urban Flow: Bike Messengers and the City.