CommuterPageBlog links to a youtube video of what a 40% bicycle mode share looks like in Copenhagen. They point out:
Copenhagen was once an auto-dominated city, however, they made a concerted effort to become a bike-friendly city. It doesn't happen by accident. Copenhagen is doubling its bicycle budget from $15 million to $30 million per year. With this commitment to cycling, Copenhagen will surpass a 40% bicycle mode split in the city to become one of the most, if not THE most, bicycle-friendly city in the world.