Our tires, despite looking perfectly normal, are over 8 PSI under-inflated! Using some data from the EPA, I did some calculations showing that if we were better about keeping our tires properly inflated, we could save 266 lbs of CO2, 14 gallons of gasoline, and about $35 each year. All this for about 2 minutes once a month.
As if this wasn’t enough, I extrapolated to the number of US cars (220 Million), and came up with the $7B, 52 billion lbs of CO2 number. The impact is tremendous, both in terms of climate change and money saved.
Yes, I have been aware of that for a while. Of course, cars should be checking their own tire pressure continually and either add the air automatically or give a warning signal.