Alcohol and drug effects — Maryland Permit Test
Alcohol and drug effects on the Maryland permit test — 6 rules, each with the reason behind it and a question on it while it is fresh.
The rules
It is illegal to drink alcohol while driving or to have an open container of alcohol in the passenger area of a vehicle.
An open container in reach means the drinking can continue while driving, which is why the container itself is the offense.
It is illegal to drive while impaired by any drug or combination of drugs and alcohol, including prescription and over-the-counter medicines, even if the drug was legally obtained.
Impairment is about the effect on driving, not whether the drug was prescribed or bought over a counter.
It is illegal to drive while impaired by cannabis or to consume cannabis in a motor vehicle, even though adult possession is otherwise legal in Maryland.
Legal to possess is not the same as legal to drive on — cannabis slows reaction time and distorts judgment of distance.
Alcohol is a depressant; even one drink can impair judgment, coordination, vision and reaction time — the skills driving depends on.
A driver who feels fine can already be worse at the job, which is why the legal limit is not the point at which alcohol starts to matter.
Only time removes alcohol from the body — roughly one standard drink per hour; coffee, cold showers, exercise, and fresh air do not speed the process.
The liver clears alcohol at a fixed rate that nothing speeds up; coffee makes a drunk driver alert, not sober.
A 12-ounce beer, a 5-ounce glass of wine, and 1.5 ounces of 80-proof liquor contain about the same amount of alcohol.
Each holds about the same half-ounce of pure alcohol, so a shot is not the modest drink it looks next to a pint.
On the test
Even a single drink can impair...
judgment, coordination, vision and reaction time. A driver who feels fine can already be worse at the job, which is why the legal limit is not the point at which alcohol starts to matter.
How this works
Most practice tests hand you a bank of questions and leave the manual somewhere else. This one puts them together.
You read one law and the reason behind it, then answer a question on that law while it is still fresh. Get it right and you move on; get it wrong and you have found the gap while it is cheap to fix, not on the morning of the exam.
Learning one rule at a time, and proving it immediately, is what turns a manual you skimmed into something you actually know — and it makes studying feel like getting somewhere rather than like waiting to find out.
Where these come from
Every rule here is checked against Maryland Driver's Manual, published by the Maryland Department of Transportation Motor Vehicle Administration, and against the state code itself. Last checked 2026-08-29.
- https://mva.maryland.gov/licenses-ids/prepare-drivers-license-test/knowledge-tests
- https://mva.maryland.gov/your-mva-guide/teens-new-drivers/learners-permit
- https://mva.maryland.gov/drivers/Pages/rookie-driver-general-learners.aspx
- https://mva.maryland.gov/licenses-ids/driver-education-safety/maryland-drivers-manuals
- https://mva.maryland.gov/media/148/download?inline=
- https://mva.maryland.gov/your-mva-guide/drivers-revoked-or-suspended-licenses/driving-under-influence-dui
- https://law.justia.com/codes/maryland/transportation/title-21/subtitle-8/section-21-801-1/
- https://law.justia.com/codes/maryland/transportation/title-22/subtitle-4/section-22-412-3/
- https://law.justia.com/codes/maryland/2013/article-gtr/section-21-706
- https://news.maryland.gov/msp/2023/08/24/stop-for-school-buses-what-are-the-laws-in-maryland/
- https://zerodeathsmd.gov/news/maryland-school-bus-laws-and-safety-tips/
- https://legalclarity.org/maryland-inspection-requirements-for-vehicles-what-to-know/
- https://law.justia.com/codes/maryland/transportation/title-22/subtitle-2/
- https://law.justia.com/codes/maryland/transportation/title-22/subtitle-2/section-22-206