SUPPLEMENTAL PRACTICE
Original unofficial supplemental practice; not DMV questions, an official test, a complete statement of law, or an exam prediction.
Cannabis and sober ride safety
Interactive practice requires JavaScript. Study the questions, answers and sources below.
Study all 6 questions, answers and sources
A friend argues, “If a substance is legal to obtain, driving after using it must be safe.” Which response best applies safety guidance?
- Legal availability does not establish safe driving. Cannabis can impair driving skills, so arrange another way to travel after using it. (correct): Correct. Legal availability does not show that driving after use is safe. Choose another way to travel.
- Legal availability is enough to treat a planned drive as safe if no crash has occurred.: Incorrect. The absence of a crash does not establish that a drive is safe. Use the safety guidance to plan another ride after cannabis use.
- The safety concern applies only when cannabis is used inside a vehicle.: Incorrect. The safety concern is impairment from cannabis use, not only where it was used.
NHTSA says cannabis can impair driving. The item asks learners to separate legal availability from a safe transportation choice; it does not state or interpret California driving law.
Source: NHTSA, Drug-Impaired Driving — Overview; Many Substances Can Impair Driving; Marijuana Impairs
On the way to a gathering, a passenger claims cannabis makes some people more alert behind the wheel and therefore improves their driving. What should the driver rely on?
- Treat the claim as unreliable: cannabis can impair skills needed for driving, so do not plan to drive after using it. (correct): Correct. Do not use cannabis as a way to improve driving or test your driving ability.
- Try it on a quiet road first, then decide whether driving feels easier.: Incorrect. A quiet-road trial still exposes the driver and others to risk and is not a reliable impairment check.
- Assume it improves driving if the person has used cannabis before.: Incorrect. Prior use does not establish that a person can safely drive now.
NHTSA says the belief that marijuana can make a person a safer driver is a misconception; it reports impairment to motor skills, lane tracking, and cognitive functions. A driver should arrange another ride rather than test their ability on public roads.
Source: NHTSA, Drug-Impaired Driving — Drug-Impaired Driving > Marijuana Impairs; misconceptions, motor skills, lane tracking, and cognitive functions
You agree in advance to drive friends home from a gathering where cannabis may be used. What plan best protects that role?
- Stay substance-free for the trip and keep another ride option available in case you become unable to drive safely. (correct): Correct. Protect the driving plan by staying substance-free and maintaining an alternate option if you cannot drive safely.
- Use cannabis early in the evening and drive later if you feel normal.: Incorrect. Feeling normal after cannabis does not establish that driving is safe.
- Drink alcohol instead of using cannabis because the driver is designated.: Incorrect. Alcohol can impair driving too; switching substances does not make the designated driver sober.
NHTSA recommends planning ahead for a sober driver when someone plans to use an impairing drug. A designated driver must remain sober for the driving task; having a backup ride accounts for a change in circumstances. Being substance-free is not a guarantee of fitness if tired, ill, or otherwise impaired.
Source: NHTSA, Drug-Impaired Driving — Drug-Impaired Driving > Responsible Behavior; plan ahead for a sober driver
You planned to take a rideshare home after using cannabis, but the ride is canceled and your car is nearby. What is the safest next step?
- Do not drive; arrange another sober ride or stay somewhere safe until you can travel without driving impaired. (correct): Correct. Preserve the no-impaired-driving decision and find another safe way home.
- Drive only on familiar streets and keep the windows open.: Incorrect. Familiar roads and open windows do not remove impairment or make driving safe.
- Wait until you feel more confident, then drive a short distance.: Incorrect. Confidence is not a dependable way to judge impairment.
NHTSA advises planning ahead for a sober driver and says people impaired by substances cannot accurately assess their own impairment. When the original ride fails, the safe response is to replace the ride plan, not use route familiarity or confidence as a workaround.
Source: NHTSA, Drug-Impaired Driving — Drug-Impaired Driving > Many Substances Can Impair Driving; limits of self-assessment; Responsible Behavior
You are hosting a get-together where guests may use alcohol or other impairing substances. A guest says they can drive because they feel fine. What should you do as the host?
- Help the guest leave with a sober driver or another safe ride instead of letting them drive impaired. (correct): Correct. Help arrange a sober driver or other safe transportation.
- Let the guest decide because only the driver can judge their condition.: Incorrect. People who are impaired may not accurately judge their condition; NHTSA recommends host intervention.
- Wait briefly, then let the guest decide whether they feel safe to drive.: Incorrect. A short pause and the guest’s own confidence do not establish that they can drive safely; arrange a sober ride.
NHTSA says hosts should make sure guests leave with a sober driver and that impaired drivers cannot accurately assess their own impairment. Coffee or a guest’s confidence is not a reliable substitute for arranging a safe ride.
Source: NHTSA, Drug-Impaired Driving — Drug-Impaired Driving > Responsible Behavior; hosts and sober departure; Many Substances Can Impair Driving; self-assessment
Before a dinner where you expect to drink alcohol, you plan to drive home and say you will decide later based on how you feel. Which change makes the plan safer?
- Arrange a sober ride before drinking rather than using your later self-assessment to decide whether to drive. (correct): Correct. Set up a sober way home before drinking; do not make the later go/no-go choice depend on perceived sobriety.
- Keep the car nearby and drive if you do not feel drunk.: Incorrect. Not feeling drunk is not a reliable test of fitness to drive.
- Choose a familiar route and decide later whether you feel able to handle the drive.: Incorrect. Familiarity with a route does not make a later self-estimate of alcohol impairment reliable.
NHTSA explains that people often cannot accurately assess their own alcohol impairment and may be impaired before they feel or appear drunk. Planning a sober ride in advance avoids relying on that self-estimate. This is a forward-looking transport plan, not a repeat of the existing held scenario about a friend who has already drunk and says they feel fine.
Source: NHTSA, Drunk Driving — Frequently Asked Questions > Can I determine my BAC?; self-assessment limits and feeling not drunk