Farm tractor and auxiliary lamps — Montana Permit Test
Farm tractor and auxiliary lamps on the Montana permit test — 5 rules, each with the reason behind it and a question on it while it is fresh.
The rules
When head lamps are required, a farm tractor or implement moved on the highway must show a white light to the front visible for at least 500 feet and a red light to the rear visible for 500 feet.
A tractor on a dark highway moves so slowly that a car can be on top of it before seeing it.
During the time head lamps are required, any farm tractor or implement of husbandry, moved on the highway, must display a white light to the front, visible for at least 500 feet and a red light to the rear, visible for 500 feet.
A farm tractor's or implement's lamps must be mounted to show the extreme left edge of the vehicle.
A wide plow sticking into the oncoming lane catches a passing driver who only sees the cab.
These lamps shall be mounted so as to indicate the extreme left projection of the vehicle.
A vehicle may have no more than two spot and auxiliary (fog) lamps.
A row of extra bright lamps on a bumper blinds everyone coming the other way.
Any vehicle may be equipped with (not to exceed two) spot and/or auxiliary (fog) lamps.
Spot lamps must be turned off when approaching another moving vehicle from either direction.
A spotlight swept across an oncoming windshield can blind that driver for seconds.
Spot lamps must be turned off when approaching another moving vehicle from either direction, and fog lamps may be used with lower head lamp beams if they do not project a beam stronger than the low beam head lamp.
Fog lamps may be used with low-beam head lamps if they do not project a beam stronger than the low beam.
Fog lamps brighter than low beams undo the point of dimming for oncoming traffic.
Spot lamps must be turned off when approaching another moving vehicle from either direction, and fog lamps may be used with lower head lamp beams if they do not project a beam stronger than the low beam head lamp.
On the test
At night, what must a farm tractor moved on the highway show to the front?
A white light seen for 500 feet. A tractor on a dark highway moves so slowly that a car can be on top of it before seeing it. Montana Driver Manual, p.16: “During the time head lamps are required, any farm tractor or implement of husbandry, moved on the highway, must display a white light to the front, visible for at least 500 feet and a red light to the rear, visible for 500 feet.”
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 Montana Driver Manual, published by the Montana Department of Justice, and against the state code itself. Last checked 2026-10-04.
- src/assets/drivers-manuals/MT.pdf (Montana Driver Manual, Revised April 2024, Montana Department of Justice, Motor Vehicle Division, retrieved 2026-09-14 and re-checked 2026-10-04; sha256 pinned in SOURCES.json)
- src/assets/drivers-manuals/MT.pages.txt (scripts/mt-text.sh: pdftotext -layout except printed pp.24-26, which are plain; the fixture every citation here was cut from and verified against; sha256 pinned in SOURCES.json)
- src/assets/drivers-manuals/MT-exam.html (Administrative Rules of Montana 23.3.121, Road Signs and Road Rules, as reproduced by the Legal Information Institute, read 2026-10-04; states the seven-miss pass mark; sha256 pinned under examSource)
- https://mvdmt.gov/forms-driver-license/ (read 2026-10-04; links the manual)