The Drug BASIC Is Public. Most Brokers Act Like It Doesn't Exist.

A carrier out of Laredo — MC-1247893, DOT-3567102 — had 24 power units, 26 inspections over 18 months, and an OOS rate of 7.8%. Zero crashes on their SAFER snapshot. No active out-of-service orders. The Unsafe Driving BASIC sat at 42nd percentile. A broker I know looked at that profile and loaded them without hesitation.

What he missed: the Controlled Substances/Alcohol BASIC was in the 89th percentile.

Two months later, one of their drivers tested positive for methamphetamine after a rear-end collision on I-10 west of San Antonio. The lawsuit named the carrier, the driver, and the broker. The broker's vetting file had a SAFER screenshot showing that 89th percentile, dated the morning of the load tender. That became exhibit one in plaintiff's discovery.

The information was there. He just didn't look at it.

What the CS/A BASIC Actually Measures

The Controlled Substances/Alcohol BASIC — listed on SAFER as CS/A — is one of the seven Safety Measurement System BASICs the FMCSA publishes. It reflects violations found by roadside inspectors during DOT inspections: positive drug or alcohol tests administered at the roadside, evidence of drug or alcohol use, or carrier-level Part 382 compliance failures that inspectors discover during Level III driver inspections and compliance reviews.

This is not the same as the Drug and Alcohol Clearinghouse.

I'll say it again because brokers conflate these constantly: the CS/A BASIC and the Clearinghouse are different instruments measuring the same underlying behavior from two different vantage points. The BASIC reflects what federal inspectors actually found in the field. The Clearinghouse reflects what employers reported through the mandatory reporting system. Both matter. You only have direct access to one of them.

Most brokers figure out pretty quickly that they can't query the Clearinghouse for a carrier's drivers. That's true. You're not a CDL employer; the Clearinghouse is built around the employer-driver relationship. So brokers tell themselves they've done what they can on the drug and alcohol front and move on.

That's where they leave money on the table — and exposure on the table with it.

The Clearinghouse vs. the BASIC — They're Not the Same Thing

The Drug and Alcohol Clearinghouse, established under 49 CFR Part 382 Subpart G, collects employer-reported violations: pre-employment test positives, random test positives, post-accident positives, refusals to test, and return-to-duty status. Employers query it before hiring and once per year for each driver on staff. It's a reporting and tracking system.

The CS/A BASIC is what happens when you take all the roadside inspection data for a carrier and score the drug and alcohol violations against the carrier fleet in the same segment. Under 49 CFR § 382.305, carriers must randomly test at least 50% of their average CDL driver count annually for controlled substances. Under § 382.301, every new CDL hire requires pre-employment testing. Under § 382.303, post-accident testing is mandatory after any fatality and after accidents where the driver receives a citation for a moving violation. When roadside inspectors find evidence that these requirements aren't being met — a driver with a positive roadside test, a carrier that can't produce documentation of its testing program, a driver who hasn't completed return-to-duty requirements — those violations roll into the CS/A BASIC.

Here's the practical takeaway: the BASIC is measuring what federal inspectors are encountering at the roadside with this carrier's drivers. The Clearinghouse is measuring what this carrier's HR and safety department are putting into the system. When the BASIC is elevated, the government has found drug and alcohol problems at this company regardless of what the employer-side reports look like.

An elevated CS/A BASIC is evidence of violations, not just risk. That's a distinction that matters enormously once a plaintiff's attorney starts asking questions.

What "Elevated" Actually Means Here

The FMCSA's general intervention threshold for most BASICs is 65th percentile — carriers above that level get prioritized for compliance reviews and investigations. For CS/A, hitting 65th percentile means the carrier's drug and alcohol violation rate is worse than 65% of carriers in the same segment.

But here's the thing about this BASIC specifically: there's no acceptable violation floor. Under Part 382, a driver operating a CMV with a blood alcohol concentration at or above 0.04% is a regulatory violation — full stop. A positive random test means the driver is out of service until completing the return-to-duty process under § 40.305. There's no "one warning" system, no de minimis exception, no context in which these violations are minor paperwork issues.

So when a carrier's CS/A percentile is anything above zero, some violations have been recorded. The percentile tells you how bad it is relative to the industry — but even a 15th percentile CS/A carrier has violations in the underlying data. I want to know what they are.

Above 65th percentile, I treat it as a hard decline. I've formalized that in my carrier selection policy. Between zero and 65th, I dig into the violation history — when were they, what kind, and has the trend improved? A carrier with two violations from three years ago and a clean inspection record since is a different conversation than a carrier with four violations in the last 14 months.

The percentile is the signal. The underlying data is the story.

The Scenario That Makes This Real

You're covering a reefer load — 44,000 pounds of beef trim moving from a processing facility in Garden City, Kansas to a distribution hub in Memphis. $7,400 rate on a three-day transit. Carrier MC-1247893 / DOT-3567102, same one from the top of this post. You've covered this lane a dozen times with them. Good communication. Shows up on time.

CS/A BASIC: 79th percentile.

You tender it. Driver falls asleep on I-40 outside Little Rock and clips a passenger vehicle, injuring two people. Post-accident DOT testing comes back positive for amphetamines.

Thanks to Montgomery v. Caribe Transport II — the unanimous Supreme Court ruling from May 2026 holding that the FAAAA does not preempt state-law negligent carrier selection claims — that suit lands in Arkansas state court, not federal. No preemption defense. The plaintiff's attorney gets discovery into your carrier file within 90 days.

In that file: the vetting pull you did the morning of the load tender. CS/A BASIC, 79th percentile, visible in the screenshot. And no documentation explaining what you did with that information — no note saying you reviewed it, no policy language saying what your threshold was, no record of any internal conversation about whether to proceed.

That deposition gets very uncomfortable very fast.

The carrier is liable for their driver. But you selected a carrier with a documented pattern of drug and alcohol program failures and you didn't write down how you made that call. Post-Montgomery, that's your problem too.

What DOTScreener Surfaces Automatically

When you run a carrier through DOTScreener, the CS/A BASIC percentile shows up in the screening summary alongside the other BASICs — not buried three clicks deep in a SAFER navigation menu, but right there in the result. Violation counts from the underlying inspection data surface with it.

That matters because in a raw SAFER snapshot, the BASIC grid is easy to skim too quickly. Most brokers doing a fast MC pull look at the overall safety rating, check the crash indicator, verify insurance is active, and move. The CS/A BASIC sits at the bottom of the grid. It doesn't have a blinking red light. You have to actively look for it.

Building the habit of checking it — and recording what you found — is the whole game.

How I Document This

For every carrier I vet, the CS/A BASIC goes into the file. Specifically:

The percentile at the time of vetting, with a timestamp. BASIC scores update monthly, and the date of your check matters if you're ever explaining your decision process in discovery.

Whether there are underlying violations in the data, and whether they're recent or historical. An older violation with a clean trend since is different from a violation from 60 days ago.

My disposition — approve, flag for review, or decline — with a brief note on why.

None of this has to be long. "CS/A BASIC: 18th percentile, 1 historical violation from 2022, no recent activity, approved" takes fifteen seconds to write. "CS/A BASIC: 79th percentile, multiple recent violations — declined, directed load to MC-9871234" takes maybe twenty.

The note isn't just for litigation protection, though it is that too. It's discipline. If you can't write down what you looked at and what you decided, you didn't really decide — you just reacted. A written decision is a real decision, and a real decision is what the standard of care actually requires.

Post-Montgomery, the question is no longer whether brokers can be held accountable for negligent carrier selection in state court. They can. The question is whether your file shows you exercised reasonable care at the time you selected the carrier. The CS/A BASIC is one of the signals that goes into that record. Ignoring it because you can't query the Clearinghouse is confusing two different things and leaving a hole in your vetting that a plaintiff's attorney will walk right through.

The information is free, it's public, and it's updated monthly. There's no excuse for not looking.

— Mason Lavallet

Founder, DOTScreener.com