The same goes for gasoline. Government officials have flogged energy efficiency for decades now, and we absolutely would love to see roads full of vehicles that merely sipped gas or, even more economically, not used it at all.
But if fewer people use gas, fewer people pay the state and federal taxes on fuel. What's a cash-strapped, tax-thirsty government to do?
If we're profoundly unlucky, a government would attempt what the state of Minnesota is looking into.
Minnesota is seeking volunteers to try out new technology that would help impose a proposed mileage tax on motorists.
In describing the initiative, Cory Johnson, the project manager for the Minnesota Department of Transportation, spun this weaselly bit of bureaucrat-speak:
"We are researching alternative financing methods today that could be used 10 or 20 years from now when the number of fuel-efficient and hybrid cars increase and no longer produce enough revenue from a gas tax to build and repair roads."
"Alternative financing methods." Uh-huh. Hammer through that sugar coating and it's just a new tax.
On the surface it appears plausible. An old joke in Minnesota is that the only two seasons of the year up there are "winter" and "road repair." If people are driving the same stretches of road using less gas, charge by the mile, so to speak, right?
Wrong, wrong, wrong. Think about what this tax system would entail.
First, there'd be a tracking system in every vehicle, keeping track of everywhere every driver went. How would you like Big Brother as your back-seat driver? Travel safely, citizen.
New cars presumably would have those systems, making the vehicles cost more. Old cars would have to be retrofitted, which would cost you, too.
Or if the government went without a tracking system, it always could install toll booths on every road . Does that seem efficient?
And with a new area to be taxed, that would require new cadres of revenue agents to enforce it, which grows an already bloated bureaucracy.
Even President Obama was against such an idea. When Transportation Secretary Ray LaHood floated an idea for a national mileage tax in 2009, the president -- to borrow someone else's vehicular figure of speech -- threw LaHood under the bus.
Iowa, Nevada and Texas reportedly are looking into similar mileage-tax schemes. They shouldn't. Instead of angling for ways to extract more money out of us, governments should just figure out ways to spend less of it.