Drug-Impaired Driving

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Just like drunk driving, driving under the influence of drugs is a crime – even if your impairment is due to prescribed medications, illicit drugs, over-the-counter medications or marijuana – medical or recreational. The legal and monetary consequences are the same, both with your time and money. According to the National Highway Traffic Safety Administration (NHTSA), a driving while impaired offense could cost up to $10,000 for first-time offenders. The California Highway Patrol (CHP) estimates the cost of an offense at approximately $13,500, which includes insurance hikes, attorney and legal fees, restricted licensing, days off work to go to court, a criminal record and more.

In 2018, 42% of all drivers killed in motor vehicle crashes, who were tested, tested positive for legal and/ or illegal drugs. 

That percentage has been increasing every year. The Office of Traffic Safety, together with our partners in law enforcement, state and federal agencies, pharmaceutical and cannabis industry associations, and concerned organizations and advocates across the state, wants to bring awareness to the California public about the dangers of drugged driving so that injuries and fatalities can be reduced on roadways.


What You Need to Know about Drug-Impaired Driving:


  • Over the past 10-15 years, more Americans have begun taking more prescription and over-the-counter medications that can impair driving. The list is long, and includes sleep aids, pain killers, anti-depressants, stimulants, muscle relaxants, allergy medications, sedatives, anti-anxiety drugs and many more. These medications can be impairing for many hours after taking, sometimes up to 24 hours.
  • Always check the label of any medication and talk to your physician or pharmacist. Any mention of not driving, operating machinery or side effect that causes brain or physical impairment needs to be taken seriously.
  • Taking prescription medication according to doctor’s orders is not a valid legal excuse for driving while impaired.

MARIJUANA (Medicinal or Recreational):

  • California’s Proposition 64, the Adult Use of Marijuana Act, went into effect November 9 making it legal for individuals 21 and older to use and grow marijuana for personal use. While smoking is permitted in a private home or at a business licensed for on-site marijuana consumption, smoking remains illegal while driving a vehicle, anywhere that prohibits smoking tobacco and in all public places.
  • Marijuana affects driving:
    • Slows your reaction time and ability to make decisions. Marijuana affects the part of the brain that controls body movement, balance and coordination and can impair judgment and memory. Studies show that driving while under the influence of marijuana negatively impacts attentiveness, perception of time and speed. Impaired memory can affect the ability to draw from past driving experiences, especially in emergency situations.
    • The higher you are, the more risks you take while driving. Studies show that drivers with only a small amount of THC in their blood can feel the effects. They often try to be more cautious, driving slower than normal, even sometimes too slow. However, greater problems arise when increasingly larger doses of THC are present in the blood. These drivers tend to weave in and out of lanes more, react slower to traffic lights and unexpected obstacles and are less aware of their speed. Overall, higher doses of marijuana tend to cause greater impairment when it comes to driving.
    • The effect of marijuana is strongest during the first 30 minutes after consumption. People who drive immediately after using marijuana may increase their risk of getting into a crash by 25 to 35 percent. The impairing effect rises rapidly and remains for some time. These affects can be delayed if the marijuana is ingested rather than smoked.


Combining alcohol with marijuana and/or impairing medications is even more dangerous than any used alone. Alcohol is a depressant and works by slowing down the central nervous system, which means that normal brain functions are delayed. It also impairs hand-eye coordination and how you process information. When marijuana or the long list of impairing prescription medications and illicit drugs are mixed with alcohol, the combination can heighten the effects of both on the body and brain.


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