The past week and a half have been noteworthy in the passenger car tire world. Last week, California proposed tire efficiency ratings and today the U.S. Department of Transportation's National Highway Traffic Safety Administration (NHTSA) issued a proposal for a national consumer information program with efficiency ratings and labels.
Both the state and federal proposals are designed to address the same concern: consumers lack information about which tires are more efficient. Armed with efficiency ratings, consumers can choose replacement tires that can cut the gasoline consumption of their current car, minivan, SUV or pickup and save money with fewer trips to the pump. If all automobile owners replaced their worn out tires with high-efficiency models, then the U.S. could save over $9.2 billion a year in fuel costs.
The California and NHTSA systems are complimentary. They both require tire manufacturers to report the same tire efficiency data (measured in rolling resistance), which is based on a common ISO test procedure. While California designates only the most efficient models as "fuel efficient tires," NHTSA shows a tire's efficiency along a continuous scale. As shown in the example below, NHTSA also combines the efficiency metric with data on traction and durability, which tire manufacturers already report to the agency.
It is important to note that tires can have excellent ratings in all three categories above: efficiency, safety and durability. The fictional tire rated above appears to be good in efficiency but not so good in the other two characteristics. Making tires that are superior in all aspects requires tire manufacturers to add technology and therefore cost to tire production. However, that additional cost, according to the National Academies of Science, is only about $8 for a set of four new tires, which can be paid back in a matter of months in fuel savings. A sound proposition for any car owner.