Highway breakdowns — Missouri Permit Test
Highway breakdowns on the Missouri permit test — 6 rules, each with the reason behind it and a question on it while it is fresh.
The rules
The cellular number to call in an emergency on a Missouri highway is *55.
It reaches the Highway Patrol directly. Knowing it before you need it is the whole point of it being printed.
The cellular number to call in an emergency is *55.
If you have vehicle trouble, get the vehicle off the road and away from traffic if at all possible, and turn on your emergency flashers.
Off the road is the first thing and the flashers are the second. Both are about being somewhere other than in a lane.
If at all possible, get your vehicle off the road and away from traffic.
If you cannot get the vehicle off the roadway, stop where other drivers have a clear view of it, and not just over a hill or just around a curve.
Those two places are where a driver arrives with no time at all. Anywhere else is better.
Do not stop just over a hill or just around a curve.
Never stand in the roadway, and do not try to change a tire if it means you have to be in a traffic lane.
A tire is replaceable. Standing in a live lane to change it is the part that is not.
Do not try to change a tire if it means you have to be in a traffic lane.
Place emergency flares behind a disabled vehicle to alert other drivers to change lanes if necessary.
Behind, because that is the direction the danger comes from. A flare beside the car warns nobody in time.
Place emergency flares behind the vehicle.
Lift the hood or tie a white cloth to the antenna, side mirror, or door handle to signal an emergency.
A white cloth reads as trouble from a long way off, and it keeps working after dark.
Lift the hood or tie a white cloth to the antenna, side mirror, or door handle to signal an emergency.
On the test
What cellular number does the guide give for a highway emergency?
Star five five. It reaches the Highway Patrol directly. Knowing it before you need it is the whole point of it being printed. Missouri Driver Guide, p.41: “The cellular number to call in an emergency is *55.”
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.
What it costs
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Where these come from
Every rule here is checked against Missouri Driver Guide, published by the Missouri Department of Revenue, and against the state code itself. Last checked 2026-09-16.
- src/assets/drivers-manuals/MO.pdf (Missouri Driver Guide, Revised August 2026, retrieved 2026-09-14)
- src/assets/drivers-manuals/MO.pages.txt (plain pdftotext over that PDF; sha256 pinned in SOURCES.json)
- src/assets/drivers-manuals/SOURCES.json (sha256, folio offset 2, folioMarker, nonLawPages and the extraction flag, each with its measured basis)