I wouldn't say they're widespread in Europe, but I moved from the SF Bay Area to Copenhagen, and they're certainly a big factor here. The "bicycle highways", completely separated and wide lanes that form major arteries through the city, make it much easier to bike to work from most places, without danger of car interference, or of being "doored" by parked cars opening their doors.
Some other efforts: 1) the traffic lights on several major arteries have been synchronized to typical bike speeds, rather than car speeds, so in good circumstances you can ride their whole length without hitting a red light (they call this a "green wave"), and 2) of the three bridges over the central harbor, one is bicycle/pedestrian-only (http://en.wikipedia.org/wiki/Bryggebroen), with another no-car bridge under construction.
Obviously other aspects also matter, such as a compact and flat city, but I think all these help considerably as well.
Doesn't Copenhagen also structure its traffic protocols around bicycle commuters? For instance, letting cyclists go on a green light several seconds before cars, in order to ensure that nearby drivers can see them?
Copenhagen has done studies [1] indicating that every mile driven accounts for some net economic loss (due to the harmful health effects of sedentary lifestyles, pollution, the cost to the commuter of gas/cars, the cost to society of maintaining automotive infrastructure), where very mile ridden constitutes a net economic gain (decreased healthcare costs due to being more active, lower personal cost of owning a bicycle, etc).
If the US spent more time looking at commuting from an economic and health perspective, we'd probably find that more government action is needed, beyond "Bike to work day"
The government has an economic incentive, since it's financially responsible for the health care costs for all of it's citizens. The US isn't fully responsible.
I'm vacationing in Copenhagen next week, drawn largely because it's one of the few places I've been that has anything approaching sane transportation. I'd love to get together with fellow hackers (I'm speaking at CopenhagenJS) on the 11th). I couldn't find your contact info. If you see this comment plz email me at jchris@couchbase.com thanks!
Some other efforts: 1) the traffic lights on several major arteries have been synchronized to typical bike speeds, rather than car speeds, so in good circumstances you can ride their whole length without hitting a red light (they call this a "green wave"), and 2) of the three bridges over the central harbor, one is bicycle/pedestrian-only (http://en.wikipedia.org/wiki/Bryggebroen), with another no-car bridge under construction.
Obviously other aspects also matter, such as a compact and flat city, but I think all these help considerably as well.