Saving on gas - tips from someone who should know - not me

The following is from someone who works in the petroleum industry.

My line of work is in petroleum for about 31 years now, so here
are some tricks to get more of your money's worth for every gallon:

* Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the gasoline, when it gets warmer
gasoline expands, so buying in the afternoon or in the evening....your gallon
is not exactly a gallon. In the petroleum business, the specific gravity
and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products
plays an important role. A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.
* When you're filling up do not squeeze the trigger of the nozzle to a fast mode. If you look you will see that the trigger has three (3) stages: low, middle, and high. You should be pumping on low mode, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. Ifyou are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you're getting less worth for your money.
* One of the most important tips is to fill up when your gas tank is HALF FULL. The reason for this is the more gas you have in your tank the less air occupying its empty space. Gasoline
evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation.
* Another reminder, if there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up; most likely the gasoline is being stirred up as the gas is being
delivered, and you might pick up some of the dirt that normally settles on the bottom.

Yes, and lastly, do not swear and curse when you pay way too much for gas. Just remember that your government a) refuses to drill in the US, b) won't tap Iraqi oil, c) helps the big auto companies suppress the development of fuel efficient cars, and d) keeps out competition with new vehicles. Don't swear and curse: instead pray and vote.