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Road safety guide · Michigan City Ford · Michigan City, IN
Drugged Driving: Facts, Risks and the Law
Alcohol is not the only thing that impairs drivers. Here is what the National Highway Traffic Safety Administration (NHTSA) says about driving after using marijuana, other drugs or impairing medicines.
56%Of drivers in serious injury and fatal crashes tested positive for a drug (2020 trauma-center study)
All 50States plus DC make drug-impaired driving illegal
20%Of surveyed drivers tested positive for potentially impairing drugs (2013-2014 roadside survey)
48%Rise in marijuana-positive weekend nighttime drivers, 2007 to 2013-2014
The short answer
Driving impaired by any drug is illegal in every state, including marijuana where it is legal and prescription or over-the-counter medicines that impair you. If you feel different, you drive different: plan a sober ride, don't let impaired friends drive, and always buckle up.
Drugged driving is illegal everywhere
NHTSA says it is illegal everywhere in America to drive under the influence of alcohol, marijuana, opioids, methamphetamines or any potentially impairing drug, whether it is prescribed or bought over the counter. Driving impaired by any substance is against the law in all 50 states and the District of Columbia, and driving under the influence of marijuana remains illegal even where marijuana laws have changed.
In a study of trauma centers from October to December 2020, 56% of drivers involved in serious injury and fatal crashes tested positive for at least one drug.
How drugs and medicines impair driving
Slower reactions
Alcohol, marijuana and other drugs slow coordination, judgment and reaction times.
Riskier driving
Cocaine and methamphetamine can make drivers more aggressive and reckless.
Combinations
Using two or more drugs at once, including alcohol, can amplify the effects of each one.
Medicines
Some prescription and over-the-counter medicines cause extreme drowsiness, dizziness and other side effects.
If a label warns against operating heavy machinery, NHTSA says that includes driving. Impaired drivers also can't accurately judge their own impairment. NHTSA's campaign line puts it simply: if you feel different, you drive different. For another kind of impairment, see our drowsy driving guide.
Marijuana and driving
NHTSA calls it a misconception that marijuana can't impair you or makes you a safer driver. It cites research showing marijuana impairs motor skills, lane tracking and cognitive functions, and a 2015 study that found THC hurts multitasking. NHTSA's Drug and Alcohol Crash Risk Study found marijuana users are more likely to be involved in crashes, though NHTSA notes that may partly reflect that marijuana users are more often young men, who face a higher crash risk generally.
| Finding | Figure |
|---|---|
| Drivers testing positive for potentially impairing drugs, 2013-2014 | 20% |
| Weekend nighttime drivers testing marijuana-positive, 2007 | 8.6% |
| Weekend nighttime drivers testing marijuana-positive, 2013-2014 | 12.6% |
NHTSA calls that a 48% increase in less than 10 years, and notes that a positive test does not necessarily mean a driver was impaired.
Make the safe choice
- If you plan to use an impairing drug, plan ahead for a sober driver.
- Don't let friends drive if they are under the influence of drugs.
- If you host a party where alcohol or other substances will be used, make sure every guest leaves with a sober driver.
- Always wear your seat belt. NHTSA calls it your best defense against impaired drivers. See our Indiana seat belt law guide.
As NHTSA puts it, impairment is impairment, no matter the substance.
Service at Michigan City Ford
The Works® at Michigan City Ford includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check. Michigan City Ford is a new and used Ford dealership in Michigan City, IN, with its own service department.
Schedule service online and see our service specials first. Michigan City Ford is at 3930 Franklin St. in Michigan City. Get directions.
Michigan City Ford service hours
| Days | Hours |
|---|---|
| Mon-Fri | 7:30 a.m.-5:30 p.m. |
| Sat | 8 a.m.-3 p.m. |
| Sun | No Sunday hours listed |
From Michigan City Ford's website, November 10, 2026.
Drugged driving FAQ
Is it illegal to drive on prescription medicine?
NHTSA says it is illegal everywhere in America to drive under the influence of any potentially impairing drug, prescribed or over the counter. If a label warns against operating heavy machinery, that includes driving.
Is driving high legal where marijuana is legal?
No. NHTSA says driving under the influence of marijuana remains illegal even in states where marijuana laws have changed.
Does marijuana affect driving?
Yes. NHTSA cites research showing marijuana impairs motor skills, lane tracking and cognitive functions, and a 2015 study found THC hurts multitasking.
How common is drugged driving?
In NHTSA's 2013-2014 National Roadside Survey, 20% of drivers tested positive for potentially impairing drugs. A 2020 trauma-center study found 56% of drivers in serious injury and fatal crashes tested positive for at least one drug.
Is mixing alcohol and drugs worse?
Yes. NHTSA says using two or more drugs at once, including alcohol, can amplify the effects of each.
More road safety guides
See our guides to drowsy driving and avoiding road rage.
Sources
Facts, statistics and safety tips are from NHTSA's Drug-Impaired Driving page, read November 10, 2026. This page is general safety information, not legal or medical advice; ask your doctor or pharmacist about your medicines. Service details, address and hours are from Michigan City Ford's own website, checked the same day. Photo is illustrative.
- NHTSA: Drug-Impaired Driving, National Highway Traffic Safety Administration (NHTSA), read November 10, 2026
- General service: The Works, Michigan City Ford, November 10, 2026
- Address and service hours (structured data), Michigan City Ford, November 10, 2026