Understanding How Marijuana Affects Driving | NHTSA (2024)

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Understanding How Marijuana Affects Driving | NHTSA? ›

Research shows that marijuana impairs motor skills, lane tracking and cognitive functions (Robbe et al., 1993; Moskowitz, 1995; Hartman & Huestis, 2013). A 2015 study on driving after smoking cannabis stated that THC in marijuana also hurts a driver's ability to multitask, a critical skill needed behind the wheel.

The THC in marijuana impairs psychom*otor skills, impedes the ability to multitask, disrupts lane tracking and cognitive functions, and divides attention from the task at hand — driving — according to several studies.

In a recent study published in Human Brain Mapping, researchers explore the effect of regular cannabis use on the neural dynamics that influence motor control. Their findings indicate that while using cannabis does not necessarily affect performance, it modifies how users perform tasks.

The use of stimulants, which are known to interfere with attention and impulse control, and to increase aggressiveness, can have an adverse impact on driving behaviour. The negative effects on driving can be intensified when stimulants are combined with alcohol, cannabis or opioids.

However, CBD oil does not alter brain functions in the same way that THC — another cannabinoid found in the cannabis plant — does. That is, producing psychoactive effects that may slow your reaction time and inhibit coordination. As such, CBD oil is unlikely to cause driving impairment.

Marijuana affects psychom*otor skills and cognitive functions critical to driving including vigilance, drowsiness, time and distance perception, reaction time, divided attention, lane tracking, coordination, and balance. Opioids can cause drowsiness and can impair cognitive function.

The percent of crash deaths involving cannabis more than doubled from 9 percent in 2000 to 21.5 percent in 2018, and the percent of deaths involving cannabis and alcohol also more than doubled from 4.8 percent to 10.3 percent. Cannabis was a risk factor for alcohol co-involvement, even at levels below the legal limit.

Although medical marijuana may not be ideal for treating every neurological condition, it has proven to be especially effective in managing seizures, multiple sclerosis, and muscular dystrophy.

Using cannabis and alcohol together enhances the effects of each, causing increased impairment, such as: Slowed reaction time. Loss of coordination and problem-solving skills. Distorted perception of time, distance and speed.

found in one of every seven weekend nighttime drivers. The survey results showed more drivers tested positive for drugs that may impair driving (14 percent) than did for alcohol (7.3 percent). Of the drugs, marijuana was most prevalent, at 7.4 percent, slightly more than alcohol.

What are three side effects drugs may have on the driving task? ›

Substance use can impair perception, cognition, attention, balance, coordination, and other brain functions necessary for safe driving. Driving while impaired by drugs or alcohol has been linked to reckless driving, car crashes, and fatal accidents.

The second most common drug found in drivers in crashes, after alcohol, is marijuana. This is followed by prescription and over-the-counter medications, which can include opioids, benzodiazepines, and antihistamines. Traffic safety studies reveal that marijuana is involved in about 18% of motor vehicle driver deaths.

However, in general, most experts advise that if you're going to eat a gummy, you should wait anywhere from eight to 12 hours before getting behind the wheel.

Those receiving cannabidiol experienced slightly more collisions (0.90 vs 0.68, p=0.57) and had slightly higher mean SD of lateral position and slower brake reaction times (0.60 vs 0.58 seconds, p=0.61) than those who received placebo. Participants were satisfied with their experiences.

CBD is a non-psychoactive cannabinoid, meaning it is not intoxicating and does not make you drowsy. After taking CBD, you can safely drive, exercise or operate heavy machinery. A rule of thumb for any medication, however, is to not drive after taking CBD for the first time.

“Among the states that legalized marijuana in 2016, the vehicle death rate increased by 6.0 percent between 2016 and 2021,” the report says. “While this is an increase, it is slightly less of an increase than the national average, which saw a 6.2 percent increase in the traffic fatality rate over the same period.

They can slow reaction time, decrease coordination, increase aggressive and reckless driving, impair cognitive function, or cause drowsiness. All of these effects can contribute to crash risk. Studies suggest that poly-drug use or combining alcohol and drugs can inflate the level of driver impairment and crash risk.

Overall, 55.8% of the injured or killed roadway users tested positive for one or more drugs (including alcohol) on this study's toxicology panel. The most prevalent drug category detected was cannabinoids (active THC) with 25.1% positive, followed by alcohol (23.1%), stimulants (10.8%), and opioids (9.3%).

Alcohol and marijuana are each associated with heightened risk of fatal crash involvement. When alcohol and marijuana are used together, there exists a positive synergistic effect on the risk of fatal crash involvement on the additive scale.