Pigovian Logic

From Holman Jenkins:

Even if you believe saving gasoline is a holy cause, subsidizing electric cars simply is not a substitute for politicians finding the courage to jack up gas prices. Think about it this way: You can double the fuel efficiency of any car by putting a second person in it. You can increase its fuel efficiency to infinity by refraining from frivolous trips.

These are the incentives that flow from a higher gas price. Exactly the opposite incentives flow from mandatory investment in higher-mileage vehicles. You paid a lot for a car that costs very little to operate—so why not operate it? Why bother to car pool? Why not drive across town for a jar of mayonnaise?