Also a tax of $75 should be attached to each bottle of wine and a 16 ounce jar of peanut butter should have a $40 tax.

Also the DNR maintains a network of state wide bike trails and charges something near $30/yr for an annual trail pass.

Also you'd have to discount the $5/mile by the effect of exercise. Perhaps its net effect is only 50 cents per mile for adults. In that case we may already be taxing bikes nearly that much, at least on average.

People laugh at me when I say bicycles are probably going to be outlawed for children soon. I'm cool with that; they laughed when I said smoking would be outlawed too. It is probably safer to buy a kid a lawn dart set or some packs of matches than a bicycle, and I'm just being honest about a minor hobby of mine. You can stack their little bodies like cordwood every year across the country, seems like a lot of death for fundamentally not accomplishing too much.

Since cyclists rarely kill others, an externality tax based on micromorts would hardly hit them at all. Compare that to motor travel, though…

  ... 9,200 sustain serious injury in a bicycle
  crash. A third of these seriously injured bicycle
  casualties are diagnosed with head or brain
  injuries (32%)

Showing 211 cyclists have a serious head injury per billion km cycled...

Discussion: http://www.aviewfromthecyclepath.com/2010/08/brain-injuries-...

Edit: accounting