6.4 Drugs, Medications & Healthy Driving
Key Takeaways
- It is illegal in New Jersey to operate a motor vehicle while under the influence of any drug, or while in possession of any drug without a valid prescription (N.J.S.A. 39:4-49.1, 39:4-50).
- After alcohol, marijuana is the drug most often found in drivers involved in crashes, impairing tracking ability, distance judgment, vigilance, and divided attention.
- A driver using prescription drugs must show proof of the prescription to law enforcement on request; without one, a prescription-only drug is treated as illegal.
- A drug-related DUI first offense committed on or after December 1, 2019 carries a 7-to-12-month licence loss and no ignition interlock, because an interlock cannot detect drugs.
- Motorists should have their eyes tested every year or two — annually after age 40 — and should let someone else drive when they are unwell, because even a stiff neck, cough, or sore leg degrades driving.
6.4 Drugs, Medications & Healthy Driving
Quick Answer: It is illegal to drive under the influence of any drug, or to drive in possession of any drug without a valid prescription (N.J.S.A. 39:4-49.1, 39:4-50). If asked, you must show proof of the prescription — without it, a prescription-only drug is treated as illegal. After alcohol, marijuana is the drug most often found in drivers involved in crashes. A drug-related first-offense DUI on or after 12/1/19 costs 7 to 12 months of licence loss and carries no interlock.
Drugged Driving Is Not a Lesser Offense
New Jersey's DUI statute, N.J.S.A. 39:4-50, covers driving "while under the influence of intoxicating liquor, narcotic, hallucinogenic or habit-producing drugs." There is no separate, gentler charge for drugs. In practice, the drug tier is in one respect harsher than the low-BAC alcohol tier:
| First offense on or after 12/1/19 | Licence loss | Interlock |
|---|---|---|
| Alcohol, BAC below 0.15% | Only until an interlock is installed | 3 months, or 7 months to 1 year |
| Alcohol, BAC 0.15% or higher | 3 months | During suspension + 12 to 15 months |
| Drug-related | 7 to 12 months | None |
The reason a drug DUI carries a fixed suspension with no interlock is mechanical: an ignition interlock is a breathalyzer, and a breathalyzer cannot detect drugs. The state therefore substitutes a longer, certain suspension for the technology it cannot use.
It is also illegal to operate a motor vehicle while in possession of any drug without a valid prescription. If asked, motorists using prescription drugs must show proof of the prescription to law enforcement. If you do not have a prescription for a drug that requires one, the drug is considered illegal.
Prescription and Over-the-Counter Medications
The labels on prescription bottles describe common side effects, and the manual's rule is simple: drugs that "may cause drowsiness or dizziness" should not be taken before driving.
- Ask a professional about how over-the-counter drugs may affect driving.
- Drugs that may affect basic driving skills include cold pills, tranquillizers, and some prescription medications.
- Never mix drugs without asking a medical professional about side effects and driving impact.
- Alcohol should never be mixed with any drugs or medications. The combination is not additive — it is multiplicative, and it is why a "couple of drinks" on top of a cold remedy can put a driver well past functional impairment while their BAC still reads below 0.08%.
Marijuana and Driving
After alcohol, marijuana is the drug most often found with drivers involved in crashes. The manual names four specific deficits, and each maps to a driving task you perform continuously:
| Deficit | What it looks like on the road |
|---|---|
| Loss of tracking ability | Failure to keep the vehicle within its lane — drifting, over-correcting |
| Distance judgment | Following too closely; misjudging gaps at intersections and merges |
| Vigilance | Loss of sustained attention: following too closely, drifting into another lane |
| Divided attention | Driving demands constant attention to traffic, roadway, weather, passengers, and gauges at once — this is the first capacity to collapse |
New Jersey's legalisation of adult-use cannabis changed nothing about driving law. Driving while impaired by cannabis is a DUI, and open or unsealed cannabis items in the passenger area of a vehicle carry the same penalty as open alcohol containers: $200 for a first offense and $250 or 10 days of community service for subsequent offenses (N.J.S.A. 39:4-51a, 39:4-51b).
Healthy Driving
The Driver Manual closes its health chapter with guidance that is easy to dismiss and regularly tested.
General health. Any health problem can affect driving. Even little problems — a stiff neck, a cough, a sore leg — can give you trouble. If you are not feeling well, let someone else drive.
Vision. Most of what a motorist does behind the wheel is based on what they see, and more than 95 percent of the information a driver needs is visual.
- Have your eyes tested every year or two; over age 40, every year.
- Good side (peripheral) vision is essential — it is what lets you see out of the corners of your eyes while looking straight ahead.
- Distance judgment matters: you should know how far you are from any object while driving.
- State law permits the MVC to retest the driving population, and the MVC may require a vision recheck at any time.
- Vision degrades with age. A 60-year-old perceives light about a third as well as a 20-year-old, which is why night driving becomes harder long before daytime driving does.
Hearing. Hearing warns you of trouble you cannot yet see — a horn, a siren, a train, the squeal of tires. New Jersey provides a hearing-impaired licence designation for motorists with a 41 dB loss or more, verified by a physician or audiologist (N.J.S.A. 39:3-11a). Deaf and hard-of-hearing drivers compensate successfully with mirrors and visual scanning; the risk lies with hearing loss a driver has not yet noticed.
Fatigue. A tired driver is a dangerous driver, and a tired driver can be as dangerous as a drunk driver. Maggie's Law (June 2003) makes it illegal to knowingly drive while impaired by lack of sleep and establishes driving while fatigued as recklessness under the vehicular homicide statute, N.J.S.A. 2C:11-5. The groups most at risk are the sleep-deprived, drivers covering long distances without rest breaks, drivers on the road through the night, anyone taking medicine that increases sleepiness or drinking alcohol, drivers travelling alone, drivers on long rural roads, young people, shift workers, and commercial drivers.
Key Exam Traps & Common Misconceptions
- Trap 1: "It's prescribed, so I'm fine." A valid prescription is a defence to possession, not to impairment — and you must be able to produce it.
- Trap 2: A drug DUI has no interlock. That is not leniency; it comes with a fixed 7-to-12-month suspension instead.
- Trap 3: Alcohol plus medication. The manual says never mix alcohol with any drug or medication, full stop.
- Trap 4: Eye exams. Every one to two years, and annually after 40 — a small number that appears in exam distractors as 5 or 10 years.
Under New Jersey law, what must a motorist do if stopped by police while using a prescription drug?
After alcohol, which drug is most often found in drivers involved in crashes, according to the New Jersey Driver Manual?
A first-offense drug-related DUI committed on or after December 1, 2019 carries what licence penalty?
How often does the New Jersey Driver Manual recommend a motorist have an eye examination?