California is aiming to increase vehicles' fuel efficiency by reducing energy loss from deformed tires.

The state Energy Commission last week proposed putting a fuel efficiency label on the top 15 percent of tires with the lowest rolling resistance within their size and load class.

The rulemaking is in response to a 2003 law, A.B. 844, which requires the development of reporting requirements for tire manufacturers and a rating system for comparing tires' fuel economy. If 6.75 million Californians replace their tires each year, the commission says, a 10 percent change in rolling resistance can improve fuel efficiency up to 2 percent and save 300 million gallons per year statewide. That is worth $30 per year for a mid-size car.

Improving rolling resistance is one of the cheapest ways to improve mileage, according to the National Highway Traffic Safety Administration. For example, the agency says, it costs about $3 for every mile-per-gallon increase from improved rolling resistance, compared with $42 per mile to reduce engine friction.

The state already has regulations covering tire pressure. The Air Resources Board recently passed rules requiring service stations to check tire pressure on all cars coming in for service. The new rule would cover all tires sold to replace tires that come with new passenger cars and light trucks.

The agency is proposing that all tires be accounted for by July 2011, but it has no timeline for when the ratings will be established. The Energy Commission has collected data on nearly 90 percent of the replacement tires sold domestically in 2006. Testing costs are estimated to be about $2.3 million for each of the three major tire manufacturers, or 0.03 percent of annual North American sales.

Said California Energy Commission spokesman Adam Gottlieb, "As with all regulations, it takes a lot of cooperation and buy-in."

Tire manufacturers do not like the rule.

Dan Zielinski, spokesman for the Rubber Manufacturers Association, said the proposal is too simplistic and requires too much information from manufacturers.

"It will fail to provide comprehensive, useful consumer information, and it requires an extensive and unnecessary burden on the manufacturer that will add costs in a particularly bad economy," Zielinski said. The state does not need to know every tire model's tread and sidewall ply, or whether it has raised lettering on the side, he said.

The association is proposing a five-tiered system to rank all tires, rather than establish a blanket fuel-efficiency threshold. Providing customers with more information will give manufacturers more of a price signal and lead to greater innovation, Zielinski said.

"The CEC proposal is bureaucratic," he said. "They want to collect data on every single tire, examine it, and then announce which tires are in and which are out. Manufacturers aren't going to know where their products stand until the regulations come out. It's not a very efficient way of encouraging manufacturers to invest."

Additionally, the association says, the federal government is due to come out with a resistance rating for tires as required by the 2007 Energy Independence and Security Act. The National Highway Traffic Safety Administration did not return calls seeking comment. 

Reprinted from Greenwire with permission from Environment & Energy Publishing, LLC., 202-628-6500