gpm
fuel efficiency requirements for automobile manufacturers are expressed in miles per gallon. and it's calculated that way. but that's wrong. it should be calculated using gallons per mile. i explain. say the requirement is 50 miles per gallon averaged over your fleet. i make a car that gets 10 mpg. and a car that gets 90 mpg. i sell equal numbers of cars. average 50 mpg right? wrong. 50 mpg is 20 gallons per 1000 miles. each type of car is driven an average of 500 miles. the 90 mpg car uses 5.6 gallons. so far so good. however the 10 mpg car uses 50 gallons. for a grand total of 55.6 gallons per 1000 miles. or 18 mpg. which isn't even close to meeting the requirements. fail. write your congressman. or better, timmer for president.