If I told you that increased fuel efficiency leads to more fuel consumption, what would you think?
Jevon’s paradox states that increases in the efficiency of the use of a resource lead to the increased usage of that resource. Throughout history, examples of this effect in action can be found. This brings me back to the topic of the gas tax. If you are of the belief that we need to reduce our consumption of gasoline, increased efficiency (and attempted legislation to increase efficiency) alone will only lead to more gasoline usage. If less gasoline usage is the goal, only a tax on gasoline will make it happen.