A tax on gasoline, whether fixed by the gallon or pegged to inflation, is just generally a bad idea, as fuel consumption is no longer a decent proxy for wear and tear on highways and bridges. And saying, "Hey, let's raise it now while gas is cheap" carries with it the idea that it should be reduced when (not if) gas becomes expensive, which is similarly goofy.
Of course, an even goofier idea is that we should let our highways and bridges fall apart even more than they are, just because of the "T" word.
The Tax That Dare Not Be Hiked
Gas prices are plunging, and the Highway Trust Fund is broke. After more than 20 years, why won’t Congress just raise the fuel tax?