Increase following distance — South Dakota Permit Test
Increase following distance on the South Dakota permit test — 9 rules, each with the reason behind it and a question on it while it is fresh.
The rules
Increase following distance on slippery roads, because you need more distance to stop.
On ice the car ahead stops in its distance, but yours slides on and on into its trunk.
Because you need more distance to stop the vehicle on slippery roads, you must leave more space in front of you.
When the driver behind wants to pass, slow down to allow room in front of your vehicle; this also lets the pass finish sooner.
With no gap ahead of you, the passing driver is stuck in the oncoming lane facing a truck.
When the driver behind wants to pass.
Leave extra distance behind motorcycles and bicycles; the chance of a fall is greatest on wet, icy, or gravel roads and on metal surfaces such as bridges, gratings, or railroad tracks.
If the rider goes down on a wet bridge grate, a close car runs right over the rider.
The chances of a fall are greatest on wet roads, icy roads, gravel roads, metal surfaces such as bridges, gratings, or railroad tracks.
Increase following distance when hauling a heavy load or pulling a trailer, because the extra weight increases stopping distance.
A loaded trailer keeps pushing the car forward, so it needs more road to stop.
The extra weight increases the stopping distance.
Increase following distance when it is hard to see because of darkness or bad weather.
In the dark, the stopped car ahead shows up late, and close behind it you run out of road.
When it is hard to see because of darkness or bad weather.
When being followed closely, allow extra room ahead so you can stop without being hit from behind.
If you must brake hard with a tailgater behind, the tailgater slams into your trunk.
Allow extra room so you will be able to stop without being hit from behind.
Give police vehicles, ambulances, and fire trucks extra following distance; they need more room to operate.
An ambulance can stop or turn without warning, and a car on its bumper crashes into it.
Police vehicles, ambulances, and fire trucks need more room to operate.
Near railroad crossings, leave extra room for vehicles required to stop there, including transit buses, school buses, and vehicles carrying hazardous materials.
A school bus stops at the tracks even with no train, and a driver following close rear-ends it.
Leave extra room for vehicles required to come to a stop at railroad crossings, including transit buses, school buses, or vehicles carrying hazardous materials (gasoline tankers, etc.)
When stopped on a hill or incline, leave extra space because the vehicle ahead may roll back when it starts moving.
The car ahead slips back a few feet on the hill and crunches into your front bumper.
Leave extra space because the vehicle ahead may roll back when it starts moving.
On the test
Why must you leave more space ahead on slippery roads?
You need more distance to stop. On ice the car ahead stops in its distance, but yours slides on and on into its trunk. South Dakota Driver License Manual, p.51: “Because you need more distance to stop the vehicle on slippery roads, you must leave more space in front of you.”
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 South Dakota Driver License Manual, published by the South Dakota Department of Public Safety, and against the state code itself. Last checked 2026-10-04.
- src/assets/drivers-manuals/SD.pdf (South Dakota Driver License Manual, Revised 11/2024, South Dakota Department of Public Safety, retrieved 2026-09-14 and re-checked 2026-10-04; sha256 pinned in SOURCES.json)
- src/assets/drivers-manuals/SD.pages.txt (pdftotext -layout, the fixture every citation here was cut from and verified against; sha256 pinned in SOURCES.json)
- src/assets/drivers-manuals/SD-exam.html (South Dakota Department of Public Safety, South Dakota Driver License Testing Information, KB0043731, read 2026-10-04; states the 80% rate; sha256 pinned under examSource)
- https://www.sd.gov/dps?id=cs_kb_article_view&sysparm_article=KB0043733 (read 2026-10-04; links the manual)