A lawmaker in Oregon (one of most bicycle friendly places as far as I understand it) has proposed a tax on cyclists to help pay for the roads. More detail is
here as posted on the Freakonomics blog. Pretty much every comment was the same, that it is ridiculous to charge all bike riders $56 every two years to register the bike. It costs $56/year there to register A WHOLE CAR! Nobody could ever realistically begin to think that a bike does even half the amount of damage on roads as a car does. Plus, it's an incredibly green form of transportation, many adult cyclists also own cars, and most municipalities collect taxes from ALL residents that go toward road upkeep. This dude must have someting against cyclists or is looking for a quick buck! Super lame. :)