Congress just sent a clear message to the transportation world: drug tests for truck drivers, airline pilots, and other safety workers are not going anywhere. Even as the Trump administration moves to reschedule marijuana, a powerful House committee voted this week to make sure those federal testing rules stay firmly in place.
What the New Spending Bill Actually Says
The House Appropriations Committee approved the Fiscal Year 2027 Transportation spending bill on June 4, 2026, in a 34 to 27 vote. Tucked inside the bill and an attached report are several cannabis-related directives that could shape how the federal government handles marijuana and workplace safety for years to come.
A key amendment added during the markup draws a hard line. The committee directed the Department of Transportation to keep testing workers in safety-sensitive positions for marijuana, cocaine, opioids, amphetamines, and PCP, regardless of where those substances end up on the federal drug schedule.
The directive covers workers regulated by five major federal agencies:
- Federal Aviation Administration (FAA)
- Federal Motor Carrier Safety Administration (FMCSA)
- Federal Railroad Administration (FRA)
- Federal Transit Administration (FTA)
- Pipeline and Hazardous Materials Safety Administration (PHMSA)
The committee stated plainly that any future changes to the legal status or scheduling of marijuana “should not be construed to alter existing Federal drug testing requirements” for safety-sensitive employees.
Why Trump’s Rescheduling Move Did Not Change the Rules
President Trump signed an executive order on December 18, 2025, directing the Department of Justice to move marijuana from Schedule I to Schedule III under the Controlled Substances Act.
That order set off widespread confusion across the trucking industry almost immediately. Then on April 23, 2026, Acting Attorney General Todd Blanche issued a final order rescheduling both FDA-approved marijuana products and state-licensed medical marijuana to Schedule III. For cannabis advocates, it was a landmark move. For truck drivers, it created a real legal gray zone.
Here is the problem at the heart of this debate: the Department of Health and Human Services sets the federal workplace drug testing guidelines, and those guidelines only authorize testing for Schedule I and Schedule II substances. Moving marijuana to Schedule III could technically strip federal agencies of their authority to require testing for it at all.
That legal gap is exactly why Congress is acting now, trying to lock in testing authority before rescheduling removes it entirely. The DOT had already issued firm guidance earlier this year. “Marijuana use is not compatible with safety-sensitive functions,” the agency said. Even state-licensed medical marijuana cannot be used to explain away a positive drug test result under federal rules.
Medical Review Officers who receive test results showing cannabis use cannot mark them as negative, even when an employee claims it was from a state-authorized medical product. The DOT explained that state-licensed medical marijuana still does not qualify as a drug approved by the Food and Drug Administration.
The Push for Smarter Cannabis Impairment Detection
Congress is not just drawing a line on testing. Lawmakers are also pushing hard for better tools to actually measure whether a driver is impaired right now, not just whether they used cannabis sometime last month.
The committee directed the National Highway Traffic Safety Administration to assess what technology is currently available or could soon be used by highway enforcement to detect cannabis presence. NHTSA has 180 days from the bill’s enactment to provide a preliminary briefing on its assessment plans. The committee also said it supports developing an “objective standard” to measure recent marijuana use and a related field test, acknowledging that nothing reliable yet exists.
Progress is being made, but slowly. The Department of Justice recently announced a potential breakthrough with a marijuana breathalyzer study, describing a portable, low-cost device built with 3D-printed material that looks like an asthma inhaler and can detect delta-9 THC without needing secondary lab analysis.
The committee also urged NHTSA to consider forming an interagency Impaired Driving Task Force. The goal would be to boost coordination between federal, state, and local agencies on crashes linked to impaired driving, a number lawmakers described as “rising” and increasingly concerning.
What the Science Says About Weed and Driving
This is where the debate gets genuinely complicated. The safety argument is simple enough: impaired driving kills people. But the science on measuring cannabis impairment is far messier than most people realize.
A 2024 scientific review found that most research reported no significant linear correlations between blood THC levels and actual driving performance. The researchers concluded there is no reliable straight-line relationship between how much THC is in someone’s blood and how impaired they are behind the wheel.
A separate federally funded report from the National Institute of Standards and Technology reached a similar conclusion. Detecting THC in breath as a single measurement cannot reliably indicate recent cannabis use. That puts law enforcement in a genuinely tough spot.
| Factor | Alcohol Testing | Cannabis Testing |
|---|---|---|
| Standard roadside test | Breathalyzer | Not yet available |
| Impairment correlation | Strong and established | Inconsistent |
| Metabolites clear quickly | Yes, within hours | No, can stay weeks |
| Legal per se limit exists | Yes, 0.08% BAC | Some states, disputed |
Cannabis metabolites can stay in a person’s body for weeks after use, long after any actual impairment has faded. That fact sits at the center of the fairness debate around current testing methods, particularly for workers who use cannabis legally on their own time in legal states.
Still, the numbers from the trucking sector are hard to ignore. Marijuana accounts for roughly 60 percent of all positive drug tests reported to the FMCSA Clearinghouse since the database launched in January 2020. In 2024 alone, more than 34,900 CDL holders tested positive for delta-9 THC. Those figures are a core reason safety advocates and Congress want these rules kept intact.
What Truck Drivers Need to Know Right Now
For any truck driver or safety-sensitive transportation worker, the bottom line is straightforward. Nothing about your drug testing obligations has changed, and the new bill signals it is not changing anytime soon.
All DOT drug testing requirements under federal regulations remain fully in effect. Pre-employment, random, post-accident, reasonable suspicion, and return-to-duty testing continue as normal. A state marijuana medical card does not protect you from a federal DOT violation.
Key things every commercial driver must understand right now:
- Using marijuana, even legally under state law, will still produce a positive DOT drug test.
- A failed test triggers mandatory removal from safety-sensitive duties and entry into a federally supervised return-to-duty process.
- The FMCSA Drug and Alcohol Clearinghouse tracks all violations and is checked by employers before every hire.
- A broader DEA administrative hearing on rescheduling all marijuana begins June 29, 2026. The legal picture could still shift further.
Industry groups have already warned that media coverage of rescheduling is creating dangerous misconceptions among workers. Workers compensation data from a 2025 industry report found that states that enacted recreational marijuana laws saw an average 7.7 percent increase in workers compensation claim frequency in the first year and a half after enactment.
Transportation Secretary Sean Duffy has been vocal on the subject. “At a time when culture is pushing and celebrating the use of marijuana, we’re not talking about the risk,” he said last October, adding that he views cannabis policy reform as sending a “dangerous” message in the context of transportation safety.
The tension between expanding cannabis rights and protecting road safety is not going away. Congress has now drawn its clearest line yet, locking the drug testing rules in place while the country works out a better way to actually measure impairment in real time. For the millions of truck drivers, pilots, and rail workers who keep America moving, that means one thing: the rules have not changed, and until a smarter system is built, the old system will keep running. What do you think about the government’s approach to marijuana testing in safety-sensitive jobs? Should more resources go toward developing real-time impairment technology? Drop your thoughts in the comments below.
