A 30-ton 5-axle HGV would be 6 tons per axle, a BMW 7-Series would be 1 ton per axle, and a heavy cyclist on a heavy bicycle would work out to around 0.05 tons per axle, so while a car might cause ~1/1000th of the wear of a heavy truck, a bicycle would cause less than 1/100000th of the wear that is caused by a car, and that's before you consider the wear that's caused according to the speed that a vehicle is traveling (it is roughly linear). So while it might conceivably be possible to tax motorists according to the level of damage that they cause to roads (with trucks paying far more than they do now, and with revenues not exceeding the costs of collection), it certainly wouldn't be possible to tax cyclists.