Consumers nationwide are seeking a class action lawsuit against oil companies for charging extra for fuel vapor. The case is based on a technique from the 1920s used for measuring a gallon of gasoline at an ambient temperature of 60 degrees Fahrenheit. Based on the principle of Boyle's Law, the contention is prices should be lower at higher temperatures when _less_ gas occupies a gallon. As a rule of thumb, gas expands 1% for every 15 degrees. Canada has already set the precedent for dynamic pricing on volume using temperature sensing flow meters. At present, there are no temperature sensors on American pumps.

Frugal folks have been passing around the tip to fill gas tanks in the morning or to stock up on fuel in the winter for years. However, the debate has raged back and forth whether there is actually any benefit to doing so. The experts at Edmunds claim there is no benefit as fuel storage is underground at controlled temperatures anyway. Perhaps in the meantime, consumers should spend less time worrying about a few pennies saved on gas pricesand more on dollars saved by improving fuel economy via conservative driving habits.