Given the cost of gasoline these days and the talk about future shortages, is it time to consider repeating the speed limit adjustment that was done in the US in the 1970s.  It is a known fact that vehicles are far more fuel efficient at 55 MPH (90 km/hr) than they are at higher speeds.  Making this change would reduce gasoline consumption for highway miles by 8-28% which is significant.  Not only will it reduce CO2 emissions at no cost, it will save drivers money and it will preserve the precious ‘dino juice’ for future generations.  Why is this not being discussed in the US and other developed countries?
https://www.theatlantic.com/technology/archive/2022/03/gas-prices-high-drive-slow/627039/