Driving While High: Why Legal Cannabis Still Creates DUI Confusion in Maryland

A recent article in The New York Sun discussed the lasting confusion in Maryland surrounding the impact of legal marijuana on road safety. Lawmakers still haven’t found a reliable way to determine what it means to drive while under the influence of the newly permitted drug. At the same time, fatal crashes continue to take place involving drivers who are “high.”

The article references a tragic case from Long Island in which an 18-year-old girl and two others died when a driver under the influence of marijuana crashed into their vehicle traveling at 93 mph. Such cases are creating national concerns, and for drivers, this may mean that getting pulled over could lead to criminal charges for drug use, even as a reliable way to determine whether someone is actively under the influence remains elusive.

A nationwide struggle to define impairment

According to the article, a six-year-long Ohio study determined that 41.9% of fatal-crash drivers had active THC in their system. The average THC levels were 30.7 ng/mL, which is far above most states’ impairment limits (2–5 ng/mL). The NHTSA also found that nationally, more than 54% of drivers who suffered serious injuries or were killed tested positive for drugs or alcohol. THC was the most common.

Despite the risks, there is no clear policy approach. Some states, including Nevada, Illinois, and Washington, use per se numeric limits. Others, such as Utah and Georgia, impose zero-tolerance standards. Maryland takes an impairment-based approach, which requires proof that the driver was “unable to drive safely.”

Maryland’s law lacks a per se limit for THC

Under Maryland Transportation Article § 21-902, prosecutors must prove actual impairment. It is not enough to show the presence of THC. Without a per se nanogram standard, charges depend largely on observations that law enforcement may document.

The main issue the state has struggled with is that THC metabolizes quickly. It often disappears from a user’s blood before law enforcement can seek a warrant. At the same time, inert metabolites can linger for days or weeks. Using those markers could lead to unfair assumptions of impairment in people who are no longer under the drug’s effects. The analysis, and, in turn, the defense strategies, in these cases are therefore far different from those in a drunk-driving case.

Why THC differs from alcohol

The New York Sun article covers the difference between alcohol and THC, and how those differences impact DUI cases. In the case of alcohol, which metabolizes in a steady and measurable manner, a blood or breath test is a fairly reliable way to test if a person is actively impaired. THC doesn’t behave like alcohol. There is no straightforward correlation between blood levels and impairment. A regular user of marijuana may test positive long after any impairment fades.

Police in Maryland are forced to rely on Drug Recognition Expert (DRE) observations and field sobriety tests. However, both of these are subjective and open to challenges. Without a reliable, unbiased roadside test, prosecutors must build their cases on officer opinions and questionably timed lab reports. At Carey Law Office, we have seen these weaknesses firsthand and know how to challenge such unscientific assumptions in court.

There is no reliable “THC breathalyzer”

While there is no equivalent to an alcohol breathalyzer that tests for THC, there are emerging methods for testing. Some methods, such as oral fluid or saliva testing and eye-movement tracking, may one day help, but they remain experimental for now. Saliva tests may confirm recent use, but that isn’t the same as determining that a person was high while driving. What’s more, there is no evidence that any of the early testing methods will become reliable anytime soon.

Without a reliable test, the issue of reasonable doubt is paramount for building a strong defense.

There are still real dangers of driving while high

While tests remain questionable, the fact is that THC impairs reaction time, attention, and decision-making. It’s important for drivers to avoid taking these risks. The New York Sun called for public safety campaigns similar to anti-drunk-driving messages that helped reduce that other form of dangerous driving.

At Carey Law Office, we encourage Marylanders to plan ahead and use rideshares, appoint sober drivers, and understand the laws before getting behind the wheel. However, the lack of a reliable test also makes it possible for false or unsupported allegations to go unchecked. In such cases, you need someone to fight for you.

How Carey Law Office protects Maryland drivers

Joseph Carey has been representing drivers across Maryland for over 40 years. We take a people-first approach and ensure that every client and their case receive individualized attention. We’re prepared to challenge unreliable evidence and toxicology reports. Our goal is to help clients understand the system, protect their records, and allow them to move forward.

Even as more states permit the recreational use of marijuana, the law has struggled to catch up with the driving-related issues that follow legalization. Until there’s a clear and fair standard, drivers in Maryland face uncertainty. Sometimes, that may result in unjust prosecution. If you’ve been accused of driving while high, an experienced local attorney can make all the difference. Contact Carey Law Office for a free consultation. We’re here to review your case, explain your rights, and fight to protect your future.