Timeline of CAFE developments.

1975Energy Policy and Conservation Act
1978First CAFE standards for cars
1979First CAFE standards for light trucks
2000NAS/DOT Study
2004CARB approves Pavley Rule
April 2007Massachusetts v. EPA
May 2007Executive Order 13432
December 2007Energy Security and Independence Act
2009EPA permits the implementation of the Pavley Rule
2010EPA/DOT finalize rules for model years 2012–2016
2011First footprint-based CAFE standard
2012EPA/DOT finalize rules for 2017–2025
January 2017Midterm Review: Final Determination
March 2017Midterm Review reopened for reconsideration
April 2018Midterm Review: Final Determination

Source: NHTSA, Summary of Fuel Economy Performance 2014 & Yacobucci and Bamberger.