Road-pricing has long been championed by economists, keen to impose more of the external costs of driving on road-users by charging them a fee that reflects not just the distance travelled (which is loosely what gasoline taxes do) but also the time and route of the journey.

ECONOMIST: Road-pricing in California

This partly reflects the emergence of long-distance telephone plans that no longer charged per minute but rather used a fixed fee.

FORBES: Inflation Isn't The Point Of Monetary Easing