Every year around the July 4th holiday, more Americans are on the road than almost any other time of year. And every year, a significant number of those crashes involve vehicles with tires that were already unsafe before the trip started.
National Tire Safety Week runs June 30 through July 4, with the U.S. Tire Manufacturers Association's theme: "Check Your Tires. Protect What Matters." It's a good prompt — not because the timing is arbitrary, but because most drivers genuinely don't know what to look for.
Here's a practical rundown.
The Penny Test (And Why a Quarter Is Better)
You've probably heard of the penny test: insert a penny into your tire tread with Lincoln's head pointing down. If you can see the top of Lincoln's head, your tread is at or below 2/32 of an inch — legally worn out in most states and time to replace.
But here's the problem: 2/32" is the legal minimum, not the safe minimum. Research from the AAA shows that wet braking distances increase dramatically before tires reach that threshold. At 4/32" — still technically legal — stopping distances on wet roads can be up to 43% longer than tires with new tread.
For a more useful check, use a quarter. Insert it with Washington's head pointing down. If you can see the top of Washington's head, you're at 4/32" or below. That's when you should start planning for replacement, not waiting until they're technically illegal.
Check Your PSI Before You Drive
Tire pressure drops about 1 PSI for every 10-degree drop in temperature — and rises similarly in heat. In summer, tires that were properly inflated in cooler months may be slightly overinflated, which reduces the contact patch and can make handling unpredictable.
Check your pressure when tires are cold (before driving, or after driving no more than a mile). The correct pressure for your vehicle is on the driver's door jamb sticker — not on the tire sidewall. The sidewall number is the maximum pressure the tire can hold, not the pressure your car needs.
NHTSA's Number: 3x Crash Risk
According to NHTSA data, vehicles with inadequate tires are three times more likely to be involved in a crash than vehicles with properly maintained tires. Tire-related crashes kill hundreds of Americans every year, and the vast majority are preventable with basic inspections.
Don't Forget Tire Age
Tread depth isn't the only indicator of tire safety. Rubber degrades over time regardless of how much the tire has been driven. Most manufacturers and safety organizations recommend replacing tires that are 6 years old or older, even if the tread looks fine.
How do you find the age? Look at the sidewall for a four-digit code after the letters "DOT." The last four digits tell you the week and year of manufacture. For example, "2419" means the tire was made in the 24th week of 2019. If any of your tires were made before 2019, that's worth taking seriously.
Signs Your Alignment Needs Attention
Misalignment causes uneven tread wear, which can sneak up on you. Signs include:
- The car pulls to one side when you release the steering wheel
- Steering wheel isn't centered when driving straight
- Tires wearing faster on one edge than the other
Alignment doesn't need to be done constantly, but if you've hit a significant pothole or curb recently, it's worth checking.
Mobile Mechanics Can Inspect Your Tires at Home
You don't need to drive to a shop for a tire safety check. A qualified mobile mechanic can come to you and assess tread depth, age, pressure, and visible damage before you head out on any holiday travel.
Visit our find a mechanic page to locate a vetted mobile mechanic in your area — or check our avoiding scams guide if you want to know how shops sometimes use tire inspections to push unnecessary services.
Safe travels this July 4th.