CVSA Brake Safety Week 2026: Know the 20% Rule
The Commercial Vehicle Safety Alliance’s (CVSA) Brake Safety Week is August 23–29. During the annual event, certified inspectors will conduct random brake system inspections on large trucks and buses across North America. Any vehicles failing the inspection will be placed out of service (OOS), affecting that company’s Compliance, Safety, Accountability (CSA) score.
Last year, 15% of all vehicles inspected during Brake Safety Week received OOS violations. Another 574 vehicles were pulled off the road in April 2026 due to brake-related violations during the CVSA’s annual unannounced Brake Safety Day.
Prepare your fleet: Follow the brakes at 20 percent rule ahead of Brake Safety Week
The top brake-related OOS violation each year is failure to meet the CVSA’s 20% defective brake rule, which means if 20% or more of the brakes are impaired. A typical 5-axle tractor-trailer has 10 brakes. If two fail inspection, the vehicle exceeds the 20% threshold and is placed OOS.
Here’s how to make sure your vehicle’s brakes are safe, roadworthy and inspection-ready.
1. Watch those drums and rotors.
They are the focus areas for this year’s Brake Safety Week. Inspect the visible portions of the drums and rotors during pre- and post-trip inspections. Look for broken drum and rotor components and signs of cracks or warping of the rotor and drums themselves.
2. Look for signs of metal-to-metal contact, such as grooves on the rotors.
On disc brakes, inspect rotors for excessive rust or corrosion. Inspectors may consider a heavily rusted rotor as inoperable.
3. Inspect the rotors.
Ensure the center vents aren’t exposed.
4. Check all brake lines and hoses.
Check for kinks, leaks, cracks, bulges or signs of chafing. Listen for hissing sounds or other indications of air leaks.
5. Test all warning lights and alarm systems.
Ensure they operate properly.
6. Verify that the slack adjusters are properly adjusted.
This maintains the correct shoe-to-drum clearance.
7. Run an air-leak loss rate test with the service brake fully applied.
Air pressure should not drop more than 3 PSI (for a single vehicle) or 4 PSI (for a combination vehicle) in 1 minute.
8. Inspect brake pads and shoes.
Ensure proper thickness and even wear.
9. Keep up with preventive maintenance (PM).
Always conduct a thorough pre- and post-trip inspection and follow your fleet’s PM schedule before operating your truck. Fleets using Penske vehicles can bring their vehicles in for a checkup at their nearest Penske location at any time.
Find a brake issue? Note it in your Driver Vehicle Inspection Reports (DVIR) and report it to your carrier so it can be fixed. Make sure all repairs meet manufacturer’s requirements and guidelines.
