I remember this:
National Maximum Speed Law - Wikipedia, the free encyclopedia a national program that had echoes in Canada. It kind of worked but mostly people just sped and paid fines. There is a lot of double-talk of wanting to be more fuel efficient on all sides, government and consumer and others...but it is glacial in actually occurring. The economy and world situations are much different than in the 70's, so it will take something else to spur a general shift in attitude on all sides.