A red octagonal sign with white letters is posted ahead of you. What does it require?

Why B is correct

The octagon is reserved for one message only: stop. No other regulatory sign uses that shape, and that is deliberate — the outline is recognisable from the back of the sign, at night, or through a dirty windscreen, at moments when the wording cannot be read at all. A lawful stop means the wheels actually stop turning at the stop line, at the crosswalk, or at the point where you can first see oncoming traffic if neither is marked. Coming to a near stop, or rolling through at walking pace, still counts as failing to stop. Once stopped, you give way to anyone already in the intersection or close enough to be a hazard, and then you move on.

Why the other options are wrong

A. Stop only when another vehicle or a pedestrian is present

Stopping only when someone else happens to be visible is the most common way drivers fail this question. The sign is unconditional: you stop every time, on every approach, whether or not you can see another road user anywhere nearby.

C. Do not enter, because the road ahead is closed to you

Do Not Enter and Wrong Way are square or rectangular red-and-white signs. The octagon never carries that meaning — it always means stop, and the shape alone is the message.

D. Slow down and yield to traffic already in the intersection

Slowing down and yielding describes a yield sign, which is an inverted triangle, not a stop sign. At an octagonal stop sign, slowing is not sufficient; the vehicle has to come to an actual halt before the stop line or crosswalk.

On the road

Think of the stop sign at the end of a quiet subdivision street where you can see three blocks in every direction. It is tempting to roll through at 5 mph. Legally, and on the knowledge test, that is still a failure to stop, and it is also exactly how drivers hit pedestrians and cyclists they never registered.

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