Keeping your drivers safe and your operation compliant is no small task. But when it comes to drug and alcohol testing, the rules are non-negotiable. If you’ve got drivers behind the wheel of commercial vehicles, you need to understand what’s required and when.
Here’s what you need to know to stay compliant, avoid penalties, and keep your fleet rolling smoothly.
Who Needs to Follow DOT Testing Rules?
If your drivers operate commercial motor vehicles (CMVs) that require a CDL—whether that’s Class A, B, or C with endorsements—and drive in interstate commerce, they’re subject to DOT drug and alcohol testing regulations (49 CFR Part 382).
This includes:
- Private and for-hire carriers
- Owner-operators
- FedEx contracted fleet drivers
- Bus and motorcoach operators
Even if someone only drives occasionally or works part-time, if they hold a CDL and might need to get behind the wheel, they’re covered.
When Are Tests Required?
DOT testing isn’t a one-and-done deal—it’s an ongoing responsibility. Here’s when testing has to happen:
Pre-employment: Before a CDL driver can hit the road, they need to pass a drug test. Alcohol testing is optional at this stage, but you can include it.
Random testing: All drivers need to be in a DOT-compliant random testing pool. For 2025, the minimum rates are:
- 50% of drivers annually for drug testing
- 10% of drivers annually for alcohol testing
Post-accident: Required when unavoidable accidents occur, especially those with fatalities or citations tied to injuries or tows.
Reasonable suspicion: If a trained supervisor sees signs of drug or alcohol use, testing must happen immediately.
Return-to-duty: If a driver has tested positive or violated your policy, they’ll need to complete the SAP (Substance Abuse Professional) process and test clean before returning to driving.
Follow-up: After a driver returns, they’ll be subject to unannounced follow-up tests for up to 5 years.
What Substances Are Tested?
DOT drug tests (urine-based) check for five types of drugs:
- Marijuana (THC)
- Cocaine
- Amphetamines (including meth)
- Opiates (like heroin, morphine, and codeine)
- PCP
Important: CBD is not an excuse for testing positive for THC. Drivers are responsible for what’s in their system.
Alcohol Testing Basics
Alcohol tests are conducted using breath or saliva samples. If a driver tests between 0.02 and 0.039 BAC, they’re benched for at least 24 hours. A result of 0.04 or higher is considered a DOT violation and triggers the return-to-duty process.
Common Mistakes That Can Cost You
Even well-meaning fleet owners miss a few steps. Keep an eye out for these red flags:
- Skipping pre-employment drug tests
- Not enrolling drivers in a random testing program
- Missing a required post-accident test
- Supervisors not trained in reasonable suspicion procedures
- Failing to check the FMCSA Clearinghouse before hiring
What’s the FMCSA Clearinghouse?
It’s a national database that tracks CDL driver drug and alcohol violations. Since 2020, all DOT-regulated employers have been required to check the Clearinghouse during hiring and run an annual query on all current drivers. If you’re not doing this, you’re out of compliance.
Final Thoughts
DOT drug and alcohol testing isn’t just about checking a box—it’s about protecting your team, your business, and the people sharing the road with your trucks.
Whether you have one truck or manage a larger fleet, staying compliant needs to be part of your core safety plan.
Not sure if you’re fully covered? Want to take the guesswork out of your compliance process? Let’s talk. Book a free demo of Linehaul Central’s safety tools and see how easy compliance can be when you’ve got the right support.
