Are there any towns in the United States that bicycle is the only preferred transportation? If not towns, then parks (not bike trails, but like...a park that at least mimics a town setup)?

I like to dream, but this would be awesome for a great vacation getaway, or even an ideal place to live. In my area we have a place called "bicycle town" but it's only 1-2 miles worth of road meant for teaching the kiddies the rules of the road and cycling safety. If there was an adult version that was 20+ mile version, it'd be a cyclegasm.

So, any towns/parks in your area that are kind of like what I described? How about outside of the US?