Minneapolis was very lucky: they inherited a large number of extremely high quality freight rail right-of-ways as the industry moved out of the city center. These are perfect for conversion in to bike paths: few hills, and routed to minimize grade crossings (and hence traffic lights). I wish they were everywhere, but building bike routes of this quality in other cities will be much harder.

Denmark seems to have built the "superhighway" from scratch, which is pretty cool. It also seems to have only cost $1.5 million. Since the average freeway costs about $1 million per mile, WHY DON'T WE HAVE MORE BIKEWAYS!?

sorry, lost my composure there.