So you've been hypermiling the wheels off that new Volt, and now it needs tires. How can you be sure the new ones meet or exceed the low rolling resistance of the original rubber so your carefully curated lifetime fuel economy average doesn't plunge? Would a set of $77 Fuzion Tourings torpedo your electric range? Might four $193 Michelin Defender tires with Green X technology pay for themselves in 65,000 miles? Possibly, but the answers for these questions aren't available...yet.

NHTSA expects to fix that next year, when a proposal for new tire labeling is unveiled for implementation by 2016. In 2001, California instigated the drive to educate consumers about tire efficiency. When other states expressed interest, NHTSA took on the issue at the federal level, working to harmonize with similar global efforts. Tire labeling protocols are now in place or pending in Japan, Korea, Europe, and Brazil, with each label tailored to its market. Europe, for example, ranks exterior tire noise and wet traction as well as rolling resistance.

To learn more, I called John Rastetter, the Tire Rack's director of tire information services. He's been closely following these developments, as his company will have to communicate said ratings for more than 500 tire lines from 20 different brands. According to John, rating traction, rolling resistance, and tread wear on a 1-100 scale is ideal because these attributes are generally at odds with each other. "When we test a category of tires, the dry traction results usually fall within a few feet. The wet traction is more telling, especially when tires trade wet traction, treadwear, and rolling resistance. We don't want manufacturers to give up too much traction to get improved rolling resistance. So it's the wet traction that really separates tires." He says NHTSA's rolling resistance testing procedures will be harmonized with those established by the ISO for Europe.

The rolling resistance ratings are based on a coefficient determined in a laboratory using a 2-meter-diameter drum. Our treadwear grade will likely be a reinterpretation of the sometimes confusing sidewall number in our present Uniform Tire Quality Grade rating. NHTSA intends to host a Web calculator to help consumers compute the total cost of ownership for a set of replacement tires, considering tire life and the fuel use of their particular car. And Rastetter says the top scores of the initial crop of tires will be capped to leave room for 10-20 years of continued development, so don't expect to see any 100s when the new labels roll out.

He adds testing and reporting will be conducted by the tire manufacturers, but notes that "there's more to lose than there is to gain by fudging numbers." Each company knows the others will test its tires, so self-policing and self-snitching should keep the industry honest.

Will new labels reveal cheaper third-world tires to be thirstier, less safe, and of lower value than the premium brands? Not necessarily. A Taiwanese Nangkang tire for the popular VW Golf in Europe currently outrates one from Continental costing 70 percent more. Of course, going forward, I expect all brands will tweak tire compounds to maximize their label ratings within one design cycle of implementation. With any luck, doing so might also raise the quality of all tires.

Illustration Kareem Rizk