On news that Americans drove 1.4 Billion fewer highway miles than at the same time last year,
[Transportation Secretary Mary] Peters expressed concern that the cutbacks have resulted in the collection of fewer taxes on gasoline. Such taxes are funneled to the federal Highway Trust Fund, which gets 18.4 cents per gallon from gasoline and 24.4 cents per gallon from diesel fuel.
“History shows that we’re going to continue to see congested roads while gas tax revenues decline even further,” she said.
So people are going to drive less, but congestion isn’t going to improve? That seems odd. I’m certain there is wiggle room. For example, perhaps the miles being cut are vacation miles, or something, and not commuter miles. Or not [emphasis mine].
Commuter rail ridership broke an all-time record this week, and Caltrans reported a dip in freeway traffic as commuters across California struggled with record gasoline prices.
I will go back and somewhat agree with Mary Peters. If fleet fuel efficiency improves, and all other things remain equal, then higher gas taxes are necessary.

I’m sorry, what? What end goal are you attempting to achieve here? Are you looking to reduce congestion by way of making driving too expensive for the average man? Or are you looking for lower emissions? Or some other alternative?
Or are you cynically trying to keep gov’t revenues up by some sleight-of-hand?
I’m assuming that driving patterns don’t change. Therefore as efficiency improves, less gas is purchased, and the Highway Trust Fund gets less revenue even though the need/demand for road maintenance and construction doesn’t change.