United States Corporate average fuel economy standards
Fuel efficiency standards remained largely unchanged for over two decades. Only recently have standards for passenger vehicles been revisited.
European Union Emissions intensity indices
Starting from a comparatively high point, real fuel taxes were almost flat since the mid-1990s and steadily declined as a proportion of the final fuel price. Rising oil prices rather than government intervention therefore were the main increase to price signals for more efficient road transport. Shown for EU27, Norway, Switzerland, and Turkey.