Could bike sharing systems be a game changer for cycling in American cities? Check these slick-nifty interactive maps from London academic Oliver O’Brien and watch 16 cities around the world do it to it.

Newbies Denver, Minneapolis and DC all have at least 500 bikes up for share, but Paris has 20,000. Density is key to success: The more stations (like Montreal above), the better. So, NYC next?