To me, the fact that the economy is not currently completely “in the tank” speaks more to the success of stimulus programs than having anything to do with adaptation to higher price levels. Countries such as Greece, Spain and Italy do not have the luxury of being able to hide the impacts of their high cost of oil. They are doing less well financially, but were not included in Hamilton’s analysis.
Easy to Overestimate Impact of Recent Changes in Vehicles
With vehicles, we are dealing with a mixture of vehicles of all ages. The average age of automobiles is now estimated to be 10.8 years. The average age of trucks is no doubt greater. The EIA provides a summary of average fuel economy by type of vehicle based on US Federal Highway Administration Data, summarized in Figure 2.
This data is only through 2010. While it shows some improvement in efficiency of light duty short wheelbase vehicles, it shows little improvement in efficiency overall. The big increases in efficiency were in the period between 1973 and 1991.
The mix of cars by type is concerning.
The percentage of automobiles has been dropping, as the number of SUV and trucks has been rising. The change between 2008 and 2010 reflects the fact that the number of “automobile” registrations dropped by 4.5% in that time-period, while the number of other (larger) vehicles rose slightly. Thus, the long-term trend to relatively more of the larger vehicles continued. Obviously, this data doesn’t show carpooling and other adaptations, but it is difficult to see any recent big trend toward efficiency.