The economics of selling gas make that pretty much impossible. It's a commodity, ie one tank of gasoline is pretty much the same as any other tank of gasoline. Therefore, if you have four gas stations on the same corner (definitely not an impossibility), they are selling the exact same thing to you and have three competitors doing the exact same thing (to say nothing of the several dozen other gas stations nearby). If you are selling the exact same thing (or close enough not to matter) as your competitor, what else do you have to compete on? Service? No... all gas stations are self-service now. That leaves price. If you want your customers, you're going to strive to be the cheapest gas on the corner.
Not only that, gasoline is an extremely price-sensitive commodity; people will literally drive miles to save a few cents per gallon. If you "gouge" your customers with a 30-cent margin, your competitors will beat you by 25 cents. Period.
There isn't a collusion to raise gas prices. If there were, gas station owners would be driving BMWs and lighting cigars from twenty dollar bills.
So, if a gas station owner purchases 50,000 gallons of gas on Monday at $3.50 a gallon, planning on selling it at $3.55 a gallon, and then the very next day something happens to cause everyone else to raise prices to $3.99 a gallon, don't you think he isn't going to raise his prices too?
I imagine, (I could be wrong, if anyone has evidence to the contrary please correct me), that gas station owners get a delivery of X amount of gallons per week, and that they are supposed to sell X amount of gallons before their next delivery date. If they sell too much, they will run out, and have to get another delivery made at an increased cost. So they pretty much keep their prices in line with their competitors. When it comes close to the next delivery date, if they have extra gas on hand, they cut their prices a little so that they will be able to accept their full delivery, because the delivery price is based on them purchasing X amount. If they don't have a lot, they may raise prices just a little over their competitors so that they can make it last until their next delivery, while still getting some customers.
Most of the Admiral gas stations I see, have pop, cigarettes, oil, candy bars, and gas, and not much else. I can't believe that the station owners of these places are barely skimping by, as they could have invested their money into a much more lucrative business.
Basically, I don't believe that the owners are that stupid.
But I could be wrong.