I saw a link on Chris Zurcher's headlines blog about how much gas you can save if you simply drive more slowly:
The Union of Concerned Scientists tells us that dropping from 70 to 60 mph improves fuel efficiency by an average of 17.2 percent. Dropping from 75 to 55 improves fuel efficiency by 30.6 percent!
Put another way, in a family sedan, every 10 mph you drive over 60 is like paying 54 cents per gallon more for gas you bought at $3.25 a gallon.That extra cost is even higher for big SUVs and other less-efficient vehicles. And the time you save by going easy on the accelerator may not add up to as much as you thought. On a 300-mile trip, driving 65 instead of 70 mph would cost you only 20 minutes -- but save money and spew less carbon.
That reminded me of my brilliant idea from January (here and here): State departments of transportation should begin campaigns to persuade drivers to slow down. One way to get the message across is to use those flashing signs that tell you when there's a traffic jam or roadwork ahead. If there are no problems to tell us about, put them toanother use: Flash a message that says, "Slow down to save gas and fight climate change. Driving 55 can save up to 30 percent."