New York City mayoral frontrunner Bill de Blasio has come a long way since his days of opposing the Prospect Park West bike lane.  At a speech Tuesday afternoon before a group of urban innovators, de Blasio said, "We see the success of the New York City’s bicycling program. Biking is up 60 percent since 2008. The designs innovated for the streets of Chelsea and the East Village are now seen in protected bike lanes on the National Mall in Washington DC, on Market Street in San Francisco and in cities across the country."

As Public Advocate, de Blasio frequently criticized Bloomberg and his DOT Commissioner, Janette Sadik-Khan, for what he called "imposing" bike lanes on communities. And one of his financial "bundlers" is Jim Walden, the lawyer for the group that sued to remove the Prospect Park West Bike Lane. 

But at a forum I moderated in Park Slope during the primary, de Blasio said he'd come to the position that his initial opposition was "wrong" and that the protected bike lane "worked."

Both de Blasio and Republican Joe Lhota spoke to conferees at the City Lab conference Tuesday, sponsored by Bloomberg Philanthropies.  Lhota, who once ran the nation's largest transit system, gave a boilerplate stump speech, focusing on things like charter schools.  And while de Blasio gave his most impassioned remarks on creating universal pre-K, he did give a well-researched introduction on the "Role of Cities as Force for Progressive Change," as he titled his speech.

De Blasio, who towered over his host, Mayor Michael Bloomberg, as he took the stage, had praise for Bloomberg at the event, which was attended by the mayor, deputy mayor Howard Wolfson, and New York's transportation commissioner Sadik-Khan.

De Blasio also gave a shout-out to the mayor for his plans on climate change adaptation.

"And in this Administration’s final year," he said, "the mayor rightly put forward a bold blueprint to bolster resiliency and protect New York City’s 520 miles of coastline from the threat of climate change – a move that I predict will influence coastal cities around the world as they grapple with this emerging threat."