I'm all for it too if they want to pay for it like motorists have to..
A lot of towns here have cycleways that end rundown and unused. Maybe if cyclist had to pay for their up keep they would stop demanding exclusive us of the road.
Cycle commuters pay for the roads as much as anyone else. Even if they don't own a car and don't have to pay car related taxes [fuel,(both fed and state) excise, license and registration, etc., most of which don't go to road improvement) ], a portion of their "tax liability" goes to infrastructure.
No one who rides a bike demanding exclusive use of the roads. We just don't want to be seen as targets by some yahoo in a truck or a soccer mom in the SUV.