Four second rule — Alaska Permit Test

Four second rule on the Alaska permit test — 3 rules, each with the reason behind it and a question on it while it is fresh.

The rules

The easiest way to calculate a safe following distance is the four-second interval method.

Counting seconds works at any speed, because a faster car covers more ground in the same four seconds.

FOUR-SECOND RULE: The easiest way to calculate a safe following distance is by the four-second interval method.
Alaska Driver Manual, p.32

To use the four-second rule, watch the back of the vehicle ahead pass a definite point and count; if you pass that point before you finish counting, you are following too closely.

A fixed point turns a guess about distance into a time you can count, which is easy to check at any speed.

If you pass the same point before you are finished counting, you are following too closely.
Alaska Driver Manual, p.32

When towing a trailer or when the road is wet or slippery, increase the four-second interval to six seconds or more.

A trailer or a slick road makes stopping take longer, so you need more time between you and the car ahead.

When towing a trailer or the road surface is wet or slippery, increase the four seconds to six or more.
Alaska Driver Manual, p.32

On the test

What following interval does the manual recommend as the easiest way to keep a safe distance?

4 seconds. Counting seconds works at any speed, because a faster car covers more ground in the same four seconds. Alaska Driver Manual, p.32: “FOUR-SECOND RULE: The easiest way to calculate a safe following distance is by the four-second interval method.”

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 Alaska Driver Manual, published by the Alaska Department of Administration, and against the state code itself. Last checked 2026-10-04.