Observing the speed limit can save drivers 91 cents per gallon of gas.

Drivers who avoid rapid accelerations can increase their fuel efficiency by 33 percent.

And, according to a 2007 Oversight and Government Reform subcommittee report, retailers could save American motorists more than $1 billion a summer by adjusting prices to match the rising temperature of gas, eliminating the “hot fuel premium.”

Understanding the “hot fuel premium” requires a basic understanding of physics. As the temperature of any liquid, including gasoline, increases, its volume also increases. However, the amount of energy that gasoline contains depends on its weight, not volume. Hot gasoline is less potent than cool gasoline, and drivers get less mileage from the hotter variety.

The wholesale gas industry uses a “standard gallon” model that compensates buyers for temperature fluctuations. However, no retailers, beside those in Hawaii, compensate for temperature change at the gas pump, which cost Americans $1.5 billion in summer 2007, according to a House of Representatives report.

Myth or fact?

The debate over temperature fluctuation continued for several years with no official analysis, prompting California to release a 149-page study on the matter. The report surveyed gas data from 2008 and 2009 and calculated that motorists would have bought 117 million fewer gallons in 2007 or saved $376.4 million if temperature compensation devices had been installed at pumps.

Although this figure may have consumers screaming for reform, the study suggested otherwise.

The report did not recommend installing temperature compensation devices at the pump because it would cost about $245 million. According to the report, retailers could raise gas prices to make up for the extra gas being sold. The only potential benefit for consumers was an increased perception of fairness, which was not evaluated in the report.

So, perhaps, stick to known methods that will increase gas efficiency.

Christopher Depcik, a Kansas University associate professor specializing in automotive engineering, gave one simple suggestion: Keep your foot off the gas pedal and coast down hills.

For more gas-saving tips, go to fueleconomy.gov.