Afternoon downpours could spell disaster for millions of road trippers this summer, thanks to an unlikely suspect – tires. New research from AAA reveals that driving on relatively worn tires at highway speeds in wet conditions can increase average stopping distances by 43% or an additional 87 feet.
With nearly 800,000 crashes occurring on wet roads each year, AAA is urging drivers to check tread depth, replace tires proactively and increase following distances significantly during rainy conditions.
“Tires are what keep a car connected to the road,” said John Nielsen, AAA’s managing director of Automotive Engineering and Repair. “Even the most advanced safety systems rely on a tire’s basic ability to maintain traction, and AAA’s testing shows that wear has a significant impact on how quickly a vehicle can come to a stop in wet conditions to avoid a crash.”
In partnership with the Automobile Club of Southern California’s Automotive Research Center, AAA conducted testing to better understand performance differences at highway speeds between new all-season tires and those worn to a tread depth of 4/32-in. on wet pavement. AAA research found that compared to new tires, tires worn to a tread depth of just 4/32-in. exhibit an average increased stopping distance of 87 feet for a passenger car and 86 feet for a light truck. It also showed a 33% reduction in handling ability for a passenger car and 28% for the light truck on average.
“AAA’s testing demonstrates the impact that tire tread has on safety,” said Megan McKernan, manager of the Automobile Club of Southern California’s Automotive Research Center. “If tested side-by-side at 60 mph, vehicles with worn tires would still be traveling at an alarming 40 mph when reaching the same distance it takes for vehicles with new tires to make a complete stop.”
While AAA’s research found that tire performance does vary by brand, price is not necessarily an indicator of quality. In fact, worn tire performance deteriorated significantly for all tires tested, including those at a higher price point.
AAA didn’t the only organization to perform tests on worn tires. Michelin North America launched a worn tire testing initiative this year, saying that worn tires should be tested to determine their long-lasting performance. Measuring this, Michelin said, can help save customers money because its allows them to choose a tire option that’s cost-effective and long-lasting.
In regards to Michelin’s findings, AAA stipulated that its testing focused on performance at low tread depths and the resulting safety implications, not long-term cost savings.
In regard to AAA’s finadings, Michelin said that AAA’s data supports its position that not all tires are created equal. The company reiterated that consumers should have information about what they can expect from their tires throughout their legal life.
“AAA, like Michelin, is committed to safety, and we are pleased that AAA has added its voice to this topic,” Michelin North America said in a statement. “The AAA research also supports our position that as tires wear, their wet stopping ability decreases. We also agree that tire degradation varies significantly among brands and even within brands. In fact, some worn tires perform better than some new tires.”
The tiremaker said wear bars are legally required for all passenger tires sold in the United States, and all tires should be designed to perform to current wear bars to resolve safety, financial and environmental concerns.
AAA advises shoppers to research options carefully before selecting a replacement tire for their vehicle and to never choose one based on price alone.
Current industry guidelines and state laws and regulations frequently recommend that drivers wait until tread depth reaches 2/32-in. to replace tires. AAA says this recommendation jeopardizes a driver’s safety and minimizes manufacturer warranty costs. AAA says tires should be replaced once the tread depth reaches 4/32-in. when stopping distances have already begun to deteriorate significantly.
The full report, fact sheet and other information regarding this study can be found on the AAA NewsRoom.