I'm not aware of any country where gas taxes cover the externalities of the emission of that carbon.

I'm also not aware of any country where gas taxes and car registration fees come close to paying for the total cost of roads.

In Virginia, there is no longer a gas tax. Roads are funded by an extra half percentage added to the sales tax. This means non-drivers now subsidize the roadways with each purchase, while people buying gas/diesel for their mowers and generators no longer do.

That said, how much toward road maintenance would you say the average commuter pays? You're looking at $214/car/year, according to the FHA and Census Bureau (see, for example, http://www.artba.org/about/transportation-faqs/faqs/#4).

How much more roadway is used by a car than a bicycle? How much less maintenance is caused by a bicycle than a car? (N.B. cars are more than an order of magnitude heavier than bicyclists; trucks are two orders more per axle.) How much do you think a bicyclist's fair share should be? How should it be measured, applied, and taxed?

As for registration, I was under the impression that was more akin to registering a firearm; it's chief purpose is enforcement of laws and property taxes, rather than offsetting the costs of highway maintenance. Is there a state where vehicle registrations are a major source of highway maintenance monies?

As your first assignment in transit 101, calculate the wear and tear on a road from a bike vs a car vs a semi.

This is nonsense. Roads that cyclists ride on in the states, which are city roads, hardly ever state highways, are paid for via sales tax, not the state gasoline taxes and registration.

Very few bicyclists just use a bicycle. Most, including myself, own a bicycle and a car, and choose the bicycle for trips where it makes sense(single person trip, short distance, safe route, no cargo).

I would be willing to bet that people like me put less wear and tear on the road since the effects of bike on asphalt are negligible.

I can't tell if this is satire.

Pedestrians, bicyclists & mass transit reduce the number of cars on the road, making the gas taxes that you pay go further. And since buses & bicycle lanes are a lot cheaper than widening the road or other measures that allow more cars on the road, as a car driver you should be happy that gas taxes go towards bicycle lanes.