The Safe Tread Alliance (STA), a national coalition of tire industry leaders, safety advocates, and nonprofit partners, is pushing to modernize tire safety standards in the United States, eliminate outdated consumer practices, and retire the “penny test” for tire tread depth.

STA noted that each year, thousands of crashes across the U.S. are linked to worn or unsafe tires. Between 2019 and 2023, the Fatality Analysis Reporting System (FARS) documented 2,740 fatal crashes and 3,136 deaths involving tire-related factors. The Safe Tread Alliance believes these tragedies can be prevented through stronger tread standards, better consumer education, and a renewed focus on proactive maintenance.

Ending the Penny Test

For decades, drivers have been told to use the “penny test” to judge tire safety by placing a penny in the tread and assuming the tire is safe if Lincoln’s head is partially covered. 

However, STA said research shows that by the time a tire reaches the penny’s benchmark of 2/32 of an inch, its stopping distance, traction, and ability to resist hydroplaning are already dangerously compromised.

“The penny test has given Americans a false sense of security for far too long,” said Alex Bebiak, a co-founder of the Safe Tread Alliance and president of the Road Ready Foundation. “When lives are on the line, good enough isn’t good enough. It’s time to retire this outdated method and give drivers a safer standard.”

Introducing the Quarter Test

To replace the outdated penny test, the Safe Tread Alliance is introducing the “quarter test” a simple, accessible method for determining when tires are no longer safe. When a quarter is placed into the tire’s tread with Washington’s head down, if the top of his head is visible, the tread depth is at or below 4/32 of an inch, the point where performance and wet-weather safety begin to drop significantly.

Independent testing has shown that vehicles with tires worn to 2/32 of an inch can take up to 87 feet longer to stop in wet conditions than those with 4/32 of an inch tread. Tires at 4/32 maintain nearly 60% better water evacuation, reducing hydroplaning risk and improving overall handling.

Most major tire manufacturers and independent organizations, according to STA, are already starting to recommend replacing tires around 4/32 of an inch due to the significant reduction in wet-weather traction at that tread depth. However, STA said the messaging is unclear, inconsistent, and contradictory.

A Call for Modern U.S. Tire Standards

STA believes it’s time for the United States to adopt tire performance standards that reflect modern vehicles, technology, and real-world road conditions. 

The organization is calling for a collaborative approach between industry leaders, government agencies, and safety organizations to ensure that tires are safe throughout their usable life, not just when they’re new.

Wet Grip or Worn Tires Regulation

On July 1, 2024, 55 of the 57 member countries of the United Nations Economic Commission for Europe (UNECE) passed into legislation a new Regulation R117.04, which is called the Wet Grip on Worn Tires, or WGWT Regulation. 

This regulation introduced a stringent test to guarantee that tires maintain a certain level of performance, particularly wet grip, even when significantly worn. This test specifically measures a vehicle's braking distance required to decelerate from 80 KM/H to 20 KM/H with a water depth of 1 MM.

“Unfortunately, United States and Canada are the two key member countries who are not required or have elected to comply, following other standards that we believe are inadequate, haven’t evolved much in decades and are in dire need to be updated,” said Jamie Ward, a Co-Founder of Safe Tread Alliance, CEO of Tire Discounters, and president of the Ohio Tire & Automotive Association (OTAA).

“The technology exists to build safer, longer-lasting tires, but policy and awareness need to catch up. In fact, many global tire manufacturers already have certain tires that meet this criteria, and others are scrambling to build tires safer to comply with the new European regulation,” Ward added. “Until we the people of the United States take a stand, our lower standards will continue to allow for worn tires that aren’t as safe to be driven on our roadways, potentially killing hundreds of Americans each year in preventable traffic accidents. Together, we can save lives, reduce waste, and build consumer confidence.”

A Nation Driving Safer Movement

The Safe Tread Alliance’s national initiative, A Nation Driving Safer, aims to reset the public conversation around tire safety through advocacy, education, and industry alignment. The campaign will roll out across the country with events, social media education, and strategic partnerships designed to empower drivers and policymakers alike.

“Unsafe tires shouldn’t be a matter of opinion or luck,” Bebiak added. “We have the data, the technology, and the responsibility to act. The quarter test is more than a tool; it’s a movement towards a new standard to save lives.”