Michelin, which has been experimenting with radio-frequency identification tags in tires since early 2003, is testing the technology with several companies, though no tires have been sold to the general public yet, a company official says.

A tag embedded in a tire's sidewall is being used to identify products, with the hope of eliminating the approximately 12 labels required on each tire by auto manufacturers and auto-parts retailers to specify which tires fit on which vehicles, says Pat King, global electronics strategist at the French tire manufacturer.

The tag is based on a new standard the automotive industry is adopting that puts it more in line with what retailers, consumer-goods suppliers, and the Department of Defense are using. That standard--the Automotive Industry Action Group's Tire and Wheel Label and Radio Frequency Identification Standard B-11--has been recently revised to support the 96-bit numeric EPCglobal data format preferred by Wal-Mart Stores Inc., the Defense Department, and others. Today, tire manufacturers must produce up to 12 labels with unique identifying marks for each tire to help tire stores and dealers recognize the tires best-suited for specific vehicles. Estimates from the U.S. Rubber Manufacturers Association puts tire-unit sales this year at approximately 323 million, up to 356 million units by 2009, with about 80% sold in the aftermarket.

There's some indication, however, that active RFID technology in the sidewall of tires that now only recognizes minimal data could mature into a temperature- and pressure-monitoring system embedded in tires. The tag would operate on a passive UHF Gen 2 specification following the ratification of the specs sometime this year by standards organization EPCglobal Inc. and integration of ISO standards from the International Standards Organization. The tag would report into the telematics system in the car, according to sources.

That's what J.B. Hunt Transport Inc., a transportation logistics company that burns through a lot of Michelin, Goodyear, and Bridgestone tires on its more than 10,000 truck cabs and 48,000 trailers, wants. "An RFID tag in the sidewall of the tire can help extend the wear of the tire and improve fuel consumption because we can quickly check them each time they come back into the yard," says Gary Wicker, senior VP of engineering services for J.B. Hunt.

Michelin has said it's working on electronic ways to enhance tire performance such as monitoring temperature, pressure, and road conditions, but King declined to discuss whether RFID is part of those efforts. The French tire manufacturer already offers a sensor application to monitor temperature and pressure. The sensor platform is battery powered and sits on the tire's rim.

The tire industry faces regulatory pressures from the National Highway Traffic Safety Administration requiring tire companies to monitor pressure and temperature in tires as part of the Tread Act, a much-publicized law passed in 2000 in response to the rollovers of Ford Motor Co.'s Explorers equipped with certain Firestone tires. The Tread Act states that the vehicle identification numbers must correlate with the Department of Transportation's number for the tire.