Comment by tzs

What are the price variations like over short distances?

In the US gasoline short distance price variations are ridiculous. I've seen it where one station was $3.50/gal and another station on the same main road just a 30 second drive away was $4.30/gal. These two stations almost always have a large difference like that. This kind of large difference over a small distance is common all over the country.

Yet a surprisingly large number of people will always choose the more expensive station, even if they know about both of them (and the other stations with prices consistently in between that are also about equally close). There's nothing about the layout of the town and traffic patterns that make the expensive station more convenient, or make it easy to find. All these stations are about equally busy so it is not like the expensive one is faster. The less expensive one even has a way better convenience store.

This is one of the higher gas price states and people are constantly complaining about how much it costs to fill up, and when I ask complainers about where they buy gas it is often the expensive stations.

Many of them think that if they don't buy at the expensive station it will be bad for their car. Different brands add different detergents and additives that fight clogging and build up of deposits in your engine and fuel system.

However in 1995 the US got a federal standard that all gas has to meet, and then in 2004 several major car makers developed a standard they called "Top Tier" which is about 20 times more effective than the federal standard. Most major gas brands now sell only gas that is certified to meet the Top Tier standard.

Most testing has found that going for something beyond Top Tier doesn't really have a significant benefit for most people. For nearly everyone the best approach is:

(1) Avoid gas that is not at least Top Tier. Generally the only places that sell gas that isn't at least Top Tier are grocery store brands and maybe some convenience store brands. The savings with those brands is usually only a couple or so cents a gallon compared to the least expensive Top Tier brands (ARCO, Costco) and your car will perform better (including improved mpg) and need less maintenance.

(2) Buy the least expensive Top Tier or above gas that is convenient. You aren't going to notice any difference in performance or maintenance if you pay extra for some brand's particular proprietary blend.