LINCOLN, N.E. -- Policy makers in the U.S. will vote later this summer whether to mandate or allow automatic temperature compensation at fuel pumps.

The National Conference on Weights and Measures will decide at its annual conference in July.

The American Trucking Associations opposes the devices, while independent truckers, backed by the Owner-Operator Independent Drivers Association have been pushing for them, even going so far as the file a class action lawsuit against a group of fuel suppliers.

So-called "hot fuel," supposedly rips off fuel buyers at the pump, consumer advocates insist. During wholesale transactions, a gallon of fuel is defined by fuel companies as being at 60 degrees. At retail, however, there is no consideration given for temperature and studies show that national average temperature of motor fuel is near 70 degrees, and even higher in warmer weather. 

Therefore, the warmer the fuel, the less measurable energy (Btu) and fewer miles to the gallons a vehicle will receive and the more fuel companies profit from the "extra" gallons created by the expansion.

Certain automatic temperature compensation devices can be installed on retail pumps to make up the difference in price. In fact, they're standard in Canada, as they are used by fuel retailers to offset profit lost to colder temperatures.

Oil companies in the U.S. have refused to outfit pumps with the technology, however.

But the issue is heating up after big box giant Costco agreed to add temperature compensation equipment to its pumps in the hottest regions of the country in order to settle a lawsuit.

The American Trucking Associations recently sent a letter to the voting members of the National Conference of Weights and Measures, opposing the devices in connection with the retail sale of diesel fuel.

ATA's letter says the use of ATC devices will disadvantage consumers by increasing the cost of retail fuel transactions and by making it difficult for consumers to compare fuel prices at the retail level.

Travel-center group NATSO has testified that the costs of ATC would outweigh any potential benefits. 

-- with files from Heavy Duty Trucking