Rule Map–>New Consumer Tire Label–>TYPES OF INFORMATION
The Energy Independence and Security Act of 2007 (EISA) requires NHTSA to “promulgate rules establishing a national tire fuel efficiency consumer information program for replacement tires designed for use on motor vehicles to educate consumers about the effect of tires on automobile fuel efficiency, safety, and durability.” This must be done by December 19, 2009.
NHTSA plans to require a new tire label showing 3 ratings:
- Fuel Efficiency: This rating would be based on rolling resistance , the energy required to keep the particular tire model rolling. According to NHTSA, “Rolling resistance is a standard measurement for characterizing and comparing tire energy performance.” Related issues for comment: the test method for determining rolling resistance; best metric for measuring it.
- Safety/Wet Traction: The safety rating would be based on traction on a wet surface.
- Durability/Tread Wear: The durability rating would be based on tread wear.
See the proposed label design.
Wet traction and tread wear ratings are part of the Uniform Tire Quality Grading Standards (UTQGS) already required by federal law. Tire manufacturers must mold this information into the sidewall. NHTSA wants to use this existing information because the statutory deadline is almost here. The test method for determining wet traction and tread wear will be the same as under UTQGS, but the new label will use a different rating formula to present the information to consumers.
Design changes that improve tire fuel economy can lower its safety and durability. A February 2009 NHTSA study found that manufacturers can avoid this trade-off by using higher-cost technologies (e.g., silica tread). Giving consumers all three ratings individually lets them see whether a particular tire model trades safety or durability for higher fuel efficiency.
NHTSA wonders whether to develop a rating that combines these 3 characteristics into a single “Overall” rating; this might be expressed as the cost per mile of buying and using the tire. This would make it easier for consumers to compare overall performance across tire models, but there are also problems with developing such a rating. First, consumers may prioritize the 3 components (safety, durability, fuel efficiency) differently. Second, it will be hard to convert traction data into cost per mile of accidents avoided.
Could a meaningful combined rating be developed? If so, should it replace the 3 individual ratings or be a fourth rating?