• DOT maintains zero-tolerance cannabis rules despite federal rescheduling: Following the DEA’s recent shift of marijuana from Schedule I to Schedule III, the U.S. Department of Transportation clarified that its strict zero-tolerance drug screening policy remains unchanged, as marijuana is explicitly named in agency regulations rather than by its federal schedule.
• State-licensed medical marijuana is not a valid excuse for failed drug tests: Under federal transit regulations, Medical Review Officers are forbidden from overturning a laboratory-confirmed positive drug test based on an employee’s use of state-licensed medical marijuana, physician recommendations, or dispensary cards, because state-dispensed cannabis lacks FDA approval and cannot be federally prescribed.

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The U.S. Department of Transportation (DOT) has issued official guidance reinforcing its zero tolerance for cannabis use, clarifying that transportation workers cannot use state-licensed medical marijuana to excuse a positive drug test.

The guidance, released this month by the DOT’s Office of Drug and Alcohol Policy and Compliance (ODAPC) alongside the Office of the General Counsel, addresses a recent Drug Enforcement Administration order that reclassified certain cannabis products—including state-regulated medical marijuana—from Schedule I to Schedule III under the Controlled Substances Act.

The DOT, for its part, has long held that reclassification would not affect how the agency approaches its drug screenings and that marijuana use, medical or otherwise, remains prohibited. The DOT told CCJ the agency is working with its interagency partners “to maintain safety in the transportation industry,” adding that nothing is changing with regard to its testing protocols. 

Marijuana, which accounts for roughly 60% of all positive drug tests among commercial drivers, remains a prohibited substance under 49 CFR Part 40, and the standard five-panel drug test used by the DOT is unchanged.

“Testing of transportation safety-sensitive employees pursuant to USDOT’s drug testing requirements remains in effect, including testing for marijuana, and is consistent with the rescheduling direction from the President’s Executive Order and the DOJ Order,” the agency noted to CCJ. 

In light of federal rescheduling, the DOT clarified this month that Medical Review Officers cannot overturn a laboratory-confirmed positive drug test or mark it negative based on an employee’s use of state-licensed marijuana. Regulators noted that state-dispensed marijuana is not approved by the Food and Drug Administration and therefore cannot be legally prescribed federally.

The agency emphasized that documentation such as state-issued medical marijuana cards, physician recommendations, or dispensary receipts do not meet federal compliance standards, and that under federal transportation regulations, any cannabis use through state-level programs or other non-prescription sources fails to qualify as a valid medical exemption.

“Marijuana use is not compatible with safety-sensitive functions,” ODAPC noted.

The clarification comes as the National Drug and Alcohol Screening Association (NDASA) has called on Congress and the Trump administration to establish guardrails for DOT drug screenings.

“[Marijuana reclassification] creates confusion that could put transportation safety at risk,” said former ODAPC Director Patrice M. Kelly.

Under current federal law, the Department of Transportation mandates drug testing for safety-sensitive workers, but it must follow testing guidelines set by the Department of Health and Human Services (HHS). Because marijuana is being removed from the Schedule I controlled substances list, HHS would be required to strip the drug from its federal testing panel, NDASA claims.

The DOT has told CCJ numerous times previously that marijuana is identified by name in its regulations rather than by its schedule or classification. “So even if it moves in its classification, we do not believe that would have a direct impact on that authority,” said then-Transportation Secretary Pete Buttigieg.

The NDASA is lobbying for a “transportation safety carveout” to preserve long-standing federal authority to test for cannabis in safety-critical roles, arguing that a narrow carveout is necessary to maintain consistency across federal agencies and ensure public confidence in national transportation safety standards, preventing individuals from working in high-stakes environments while impaired.

Highway bill tackles drug screenings

The first draft of the highway bill, the text of which was published this week, outlines a series of updates to drug testing parameters, adjustments to administrative fee transparency, enforcement of tracking accountability after major accidents, and expansion of certified specimen testing methods.

The proposed bill tasks DOT with managing or reforming the fee structures associated with checking and submitting driver histories to the federal drug and alcohol database.

it also directs federal regulators to adjust workplace testing definitions to officially recognize hair samples as an approved specimen type. Specifically, the bill orders the revision of “part 40 of title 49, Code of Federal Regulations, and other regulations as necessary, to recognize hair as an approved specimen type to be collected under transportation workplace drug and alcohol testing programs required under such part.”

The proposal places strict records-retention demands on employers following highway safety incidents. Within 90 days of enactment, federal regulations must be revised to require employers to keep all records of required post-accident alcohol or controlled substance testing for a minimum of 5 years. If an employer fails to produce proof of post-accident drug or alcohol testing within the federally prescribed time window, it will automatically be counted as a violation. These tracking failures will be fed directly into the Safety Measurement System to impact the carrier’s public safety profile under the Compliance, Safety, and Accountability (CSA) Program.

Elsewhere in the bill, the text expands standard state safety grant parameters to let local agencies use federal highway funds to acquire advanced field-testing equipment. This explicitly permits funding for “oral fluid screening technologies” and equipment aimed at boosting the “scope, quantity, quality, and timeliness of forensic toxicology chemical testing” to better intercept impaired drivers on the road.

Section 4003 also authorizes up to $24 million annually by FY 2031 for a multi-agency collaborative research effort to specifically map out roadside testing technologies and toxicological benchmarks for tracking marijuana and polysubstance impairment.