This recent report by University of Michigan Transportation Research Institute by Michael Sivak and Brandon Schoettle does a timely evaluation of fuel economy by examining historical data for all vehicles on US roads from 1923 to 2013. The report draws upon available travel and fuel use data by vehicle type and class to draw its conclusions. The results indicate a slight decline in fuel economy with an average of 14 mpg in 1923 to a low of 11.6 mpg in the muscle car days of 1973. After a fuel embargo crisis limited the availability of gas at the pump for drivers that year subsequent changes in the vehicle fleet caused a relatively steep boost in fuel economy reaching 16.9 mpg by 1991. Slow inexorable improvements in fuel economy brought the fuel economy levels to 17.6 in 2013. This is an interesting report that could provide support as a baseline if looking at a gas tax increases or transportation related environmental questions in your state. For more information a link to the report abstract is as follows:
If you would like to break out your spreadsheets and look at this interesting topic more closely secure a copy of the complete report via the sponsoring agency at www.umich.edu/~umtriswt.
The bibliography provides links to data sets available via US DOT as well as the Departments of Commerce and Energy.
~Thanks to Craig Copelan for this post