Also – fuel-efficient cars tend to be lighter, on average, than gas-guzzlers. This means they place less wear and tear on the road. Under a VMT tax, the driver of a Hummer would pay the same tax amount as the driver of a Prius over the same distance. The Hummer driver still has the disincentive, since he uses more fuel and pays more because of it; but his tax burden is not any higher.

I also agree that trucks need to be taxed more heavily for the damage they cause to roads. Perhaps a separate, and higher, tax on diesel fuel would accomplish this, rather than a whole new tax? It would annoy drivers of some European imports, but most consumers would probably get behind such a tax if the rationale was explained.

I personally feel that the VMT system, which has successfully been implemented in Oregon, is a perfect solution for our transportation funding problems. Not only will the VMT system create a reliable source of income, but the VMT system is also a policy that will promote the use of public transit. With the VMT system enacted, drivers will be more conscious about the amount of miles that they drive, for they will be forced to pay more accordingly. Americans will therefore start becoming more conscious about driving their cars to destinations that they can easily get to by more sustainable means of transportation.

While one draw back of the VMT system may be that there will be no incentives to drive fuel-efficient cars, the government can pay out refunds to those who own fuel-efficient cars in order to promote further sustainability. If the government does not offer these refunds to fuel-efficient car owners, than they will pay the same amount of taxes that a person driving a Hummer the same distance in a year will owe.

The first is proportional to gas consumption, so it should be accounted for by a gas tax. The current tax is too low to fully offset it, so it should be increased, paying into the general fund and allowing the federal government to reduce income taxes and increase social spending.

The second is proportional to the fourth power of vehicle weight, and is best handled via some tax on trucking. Cars are trivial here: the difference between a 20-ton truck’s wear on the road and a 20.0025-ton one’s is the same as that between a 3-ton SUV’s and a 1-ton sedan’s.

The third is not a national problem; it’s localized to a few congested arteries, and is best solved by a congestion tax. Singapore, Stockholm, and London have all implemented it in their CBDs, reducing congestion in the process.

Congestion pricing on FHTF funded roads would be a better supplement for the gas tax than a VMT tax, since it will can charge all vehicles, whether running on gasoline or not, and even more importantly since it can avoid the “need” for much new highway construction, which is driven by congestion caused by giving away a scarce resource for free.

Another supplementary tax could be a three tier vehicle excise that drip feeds into the FHTF accounts … twice the standard rate for vehicles below current fleet fuel efficiency, the standard excise on vehicles at the current fleet fuel efficiency, and excise free for vehicles at twice the current fleet fuel efficiency.

A third supplementary tax could be a per year registration tax, assessed on vehicle weight. Down the track, that could be converted to a mileage and weight tax schedule … but there’s no pressing need to solve the problem of financing rural, suburban and interstate road construction when nobody is using gasoline … we can cross that bridge in the happy day when we come to it.

For those states that already require a regular vehicle inspection, this isn’t a big deal, and the inspection process can be amended to include mileage reporting.

However, the institution of a brand new, federally-mandated vehicle inspection regime, solely for the purposes of assessing taxes, would make for a massive populist revolt, especially in the intermountain west. No politician with a skin worthy of self-preservation would seriously consider this behind closed doors, let alone in public.