Fighting the last war over again is a bad strategy for future military planning. Using science of the past in crafting technology policies for the future is just as foolish. Yet that’s what’s happening in the debate over refilling the Highway Trust Fund’s depleted financial tank.

For most of its 58-year history, the trust fund was topped off with revenues from gasoline and diesel fuel taxes. But the federal tax rate has remained unchanged at 18.4 cents per gallon for gasoline and 24.4 cents for diesel fuel since 1993. Inflation has eaten away at the fund’s ability to pay for repairs of highways, bridges and other transportation infrastructure, which the American Society of Civil Engineers says warrant a grade of D+ for their condition.

For the moment, let’s set aside the infrastructure needs that have been mounting during decades of neglect and consider what it would take to compensate the trust fund for 21 years of declining purchasing power. That is the approach Sens. Christopher S. Murphy, D-Conn., and Bob Corker, R-Tenn., have taken in proposing first to raise the gasoline and diesel taxes by 12 cents over the next two years and then to index fuel taxes to inflation in future years.

But opponents, for whom any tax increase is anathema, don’t want to do either. What they want for the most part is not clear, since Congress decided to kick the trust fund can down the highway by adopting a 10-month stop-gap measure before leaving town for a five-week summer break.

It’s probably too much to expect the House and Senate to return to the fund’s needs until next spring, but in the interim, members ought to do a little homework. They should take the time to examine how scientific advances affect the policy calculus, and then do some simple arithmetic. That’s what Rep. Earl Blumenauer, D-Ore., did, and his companion bills reflect those efforts.

The first bill, HR 3636, would provide a short-term fix, more or less echoing the Murphy-Corker proposal. Blumenauer’s legislation would increase the fuel tax by 15 cents over three years and index it to inflation thereafter. There’s nothing cutting edge here.

But, his second bill, HR 3638, is revelatory. It recognizes that gasoline and diesel use will drop dramatically as scientific and technological advances enable cars and trucks to become increasingly more fuel efficient. That is the premise of the 2012 fuel economy (CAFE) standard, which requires new cars and light-duty trucks to achieve an average of 54.5 miles per gallon by 2025, about twice what it is today.

So here’s the arithmetic. Absent a major change in driving habits, doubling the fuel use standard will halve the fuel tax revenues. In other words, indexing the tax to inflation won’t keep the trust fund solvent.

And here’s where science comes in. In the not too distant future, physics and chemistry research will likely lead to new battery technologies and make all-electric cars the vehicles of choice for most Americans. When that happens, a gas tax of even $100 per gallon wouldn’t be able to sustain the trust fund.

So Blumenauer’s bill wisely calls for road usage fees to replace taxes on gasoline and diesel fuel. To that end, HR 3638 would establish a competitive grant program to seek the best ways of tracking the number of miles traveled by vehicles and establishing payment procedures that would be enforceable and still safeguard privacy.

Blumenauer’s legislation is based on the science of the future, not the science of the past. And it sets a standard for other lawmakers to follow. When and if the stalled Shaheen-Portman energy efficiency bill (S 761) re-emerges from the Senate holding pen, for example, its sponsors should take a cue from Blumenauer and make certain its provisions are not rooted in the past.

Critics of state-of-the-art lighting, heating, building and industrial standards, such as Rep. Michele Bachmann, R-Minn., should wake up from their Rip Van Winkle slumbers and smell the 21st century coffee. They should remember the world of tomorrow will reflect the science of tomorrow. And the policies of tomorrow are best not shaped by the science of yesterday.

Michael S. Lubell is the Mark W. Zemansky professor of physics at the City College of the City University of New York and director of public affairs of the American Physical Society.