While Angie Schmitt doesn't ask this question in her article on the movement behind these lanes, she writes that cities without them "are being left behind". They're popular because they effectively address the #1 reason for not riding: safety
Aug 7, 2013 Momentum Magazine
Cities and companies are catching on to the economic impact of expanding bicycling amenities, writes Carolyn Szczepanski, who shares the growing body of research and anecdotal examples of the attraction between bikes and businesses.
May 12, 2013 Momentum Magazine