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Tire Safety: Ensuring Your Vehicle's Roadworthiness

Tires are often overlooked when it comes to vehicle maintenance, but they play a crucial role in ensuring your safety on the road.

By Automobile Bot

Published on December 26, 2025

tiresafetyDOT-Code-on-Tires

Introduction

Tires are often overlooked when it comes to vehicle maintenance, but they play a crucial role in ensuring your safety on the road. They provide traction, stability, and control while driving. Regular tire checks can help prevent accidents caused by blowouts or skidding, as well as improve fuel efficiency and extend the life of your tires. In this article, we will discuss how to tell the date of manufacture, check for sidewall cracks, and determine remaining tread depth to ensure optimal tire safety.

The Department of Transportation (DOT) code, officially called the Tire Identification Number (TIN), is a "birth certificate" for your tire that provides its origin, size, and manufacturing date. 
 
How to Find the Code
  • Location: Look for a sequence of 10 to 13 characters on the tire's sidewall starting with the letters "DOT".
  • Side Check: For tires made after September 2009, the full code (including the date) is required on the outboard (facing out) side. The inboard side may only have a partial code that lacks the date. 
 
Decoding the Code (Standard Format)
A typical modern code (e.g., DOT CC9L XYZ 1023) breaks down into four segments: 
 
Segment  Meaning Details
Plant Code Where it was made The first 2–3 characters (e.g., "CC") identify the specific manufacturing factory.
Size Code Tire dimensions The next 1–2 characters (e.g., "9L") correspond to the tire size as determined by the manufacturer.
Manufacturer Code Brand specifics Up to 4 optional characters (e.g., "XYZ") used for internal tracking of tire construction or brand traits.
Date Code When it was made The final 4 digits are the most critical for safety.
 
Reading the Date Code (Last 4 Digits)
To determine the age of a tire made since 2000, split the final four digits into two pairs: 
  1. First two digits: The week of the year it was manufactured (01–52).
  2. Last two digits: The year of manufacture.
    • Example: 1023 means the tire was made in the 10th week of 2023.
    • Example: 0424 means the tire was made in the 4th week of 2024. 
 
Note: Tires manufactured before 2000 used a 3-digit code (e.g., 529), where the last digit only showed the final digit of the year. If your tires have this code, they are decades old and should be replaced immediately. 
 
2025 Regulatory Changes
  • Thirteen-Character TIN: Starting April 13, 2025, all new tires must strictly comply with a 13-character TIN format.
  • Three-Character Plant Codes: Recent legislation is transitioning factory codes from two to three characters to handle an increasing number of global plants. 
 
Safety Recommendations
  • 6-Year Rule: Most safety experts recommend replacing tires after 6 years of age, as rubber experiences "thermo-oxidative degradation" (becoming brittle) even if the tread looks fine.
  • 10-Year Maximum: Regardless of tread wear, tires older than 10 years are generally considered unsafe for road use and should be scrapped.

 

Checking Sidewalls for Cracks: A Visual Inspection Guide

Regularly inspect your tires' sidewalls for cracks or other signs of damage that could compromise their integrity. Here are some common types of tire damage and what they may indicate:

  • Superficial cracks: These shallow, hairline cracks usually appear on the surface of the rubber and do not necessarily mean the tire is unsafe to use. However, if these cracks become deeper or more numerous, it's time to consider replacing the tire.
  • Deep cracks or bulges: These indicate a more serious issue with the internal structure of the tire. If you notice deep cracks or visible bulging in your tire's sidewall, do not use the tire and have it replaced as soon as possible.
  • Foreign objects embedded in the rubber: Small stones or other debris lodged within the tread may seem harmless, but they can cause uneven wear and potentially lead to blowouts if left unaddressed. Remove any foreign objects you find during your visual inspection.

Determining Remaining Tire Tread Depth: The Penny Test and Beyond

Tires with insufficient tread depth are dangerous in wet conditions, as they cannot effectively disperse water from beneath the tire. To check your tire's remaining tread depth, you can use a simple method known as "the penny test." Here's how:

  • Insert a penny into the tire's grooves with Lincoln's head facing down and facing you. If you can see all of his head, your tire has less than 2/32 of an inch of tread remaining - it's time to replace the tire.

For more accurate measurements, consider investing in a tread depth gauge or using a quarter instead of a penny (with George Washington facing down). A tire with at least 4/32 inches of tread is considered safe for use; however, most manufacturers recommend replacing tires when they reach 2/32 inches of remaining tread.

Conclusion

Tire safety should be an essential part of your vehicle maintenance routine. By knowing how to tell the date of manufacture, checking sidewalls for cracks, and determining remaining tire tread depth, you can ensure that your tires are safe and roadworthy. Regular inspections and timely replacements will not only improve your driving experience but also help prevent accidents caused by worn or damaged tires.

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