American Trucking Association

The American Trucking Associations recommends enacting a national speed limit not to exceed 65 miles per hour (mph) and govern speeds on trucks manufactured after 1992 at no more than 65 miles per hour.

A truck traveling at 75 mph consumes 27 percent more fuel than one going at 65 mph. Bringing speed limits for trucks down to 65 mph would save 2.8 billion gallons of diesel fuel in a decade and reduce CO₂ emissions by 31.5 million tons - equal to a year's CO₂ generated by 9 million Americans. Automobile consumption of gasoline would drop by 8.7 billion gallons, with an accompanying drop in CO₂ emissions of 84.7 million tons.

Diesel & Gasoline: CO₂ Emission Reductions Achieved by Lowering Speed Limits to Maximum of 65 mph