Yesterday, we discussed the problem of America's crumbling roads and bridges. Taxes on gasoline are meant to keep that stuff up to snuff, but the costs of maintenance and upgrades are outpacing revenue. The reason? The federal gas tax hasn't risen since 1993.

The Wall Street Journal recently examined several ways to boost funding for America's infrastructure, and we briefly discussed the pros and cons of each. But what neither we nor the WSJ explored in depth was the effect of hybrid and electric vehicles on the gas tax -- and, ultimately, road maintenance.

Here's the problem: the distance that we drive each year has been growing. Last year, Americans traveled roughly 3 trillion miles, or about 16,000 round-trip drives to the sun.

An increasing number of the cars on our roads are fuel-efficient hybrids, and fully electric vehicles will soon become commonplace, too. Even conventional vehicles will see fuel economy rise dramatically over the next 13 years. Even if the number of cars on U.S. roads continues to climb (which isn't a sure bet), fuel consumption may not ramp up at the same pace.

So, if gas consumption stagnates -- or worse, falls -- gas-tax revenue does, too. Which means that our highways and byways might soon be disintegrating exponentially faster than they are today.


We could play the role of Doubting Thomas, insisting that conventional gas and diesel vehicles will remain dominant for the forseeable future. If that's the case, some kind of restructured gas tax, like one pegged to the inflation rate, might buy us a bit of time.

But whether it happens in 18 years or 80, one day, motorists' consumption of fossil fuels will decrease and eventually dry up.

What the heck do we do then?

Assuming that sci-fi wonders like plasma-powered cars are still centuries away and that room-temperature superconductors are on the same schedule, we need to deal with the fact that we'll be moving around in wheeled vehicles -- autonomous vehicles, perhaps, but wheeled vehicles all the same.

If that's the case, there are at least two ways to address the problem of wear and tear on our roads:

1. Charge drivers (and passengers, too) for the miles they travel. This would be much like today's system of toll roads -- or perhaps, more like train ticketing systems. While this plan seems fair, it would require a great deal of government oversight, including monitoring of every individual's movement. Privacy advocates would likely pitch a fit, much as they do today.

2. Tax cars, not fuel. This puts the burden on car owners, which admittedly seems fair. The downside is that it's technically a tax increase, which is likely to be politically unpopular (though perhaps not as unpopular as option #1). 

Surely there are other ways to fund maintenance of America's infrastructure. Do you have any out-of-the-box suggestions? Feel free to share them in the comments below.


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