School bus stop arm

A stop sign that swings out from a stopped school bus.

Also known as: Bus stop arm, School bus sign

Road & transportSafety & hazardStandard profile

Meanings

In North America a school bus deploys a stop sign on a hinged arm, and traffic in both directions must stop while it is out. It is one of very few instances where a moving vehicle carries a legally binding traffic sign.

Officially standardisedVerified fact
Requires traffic in both directions to stop while a school bus is loading, deployed as a hinged octagonal sign on the bus's side.
Contexts: Road signage
Officially standardisedVerified fact
Is among the few cases in which a vehicle rather than the highway authority displays a legally binding traffic control device.
Contexts: Road signage

Visual description

An octagonal red sign lettered in white, mounted on a hinged arm that swings out from the side of a bus.

Symmetry: radial
Orientation: upright
Colours: red, white

Confidence

IdentityHigh confidence: High confidence because the identity is documented in encyclopedic references, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

Convention on Road Signs and Signals (Vienna, 8 November 1968), consolidated text
United Nations Economic Commission for Europe · retrieved 2026-07-31
A treaty binding only on its contracting parties. It prescribes sign categories, shapes and colours and permits national variants within them; it does not describe the signage of non-signatory states, notably the United States. Cited for category and design prescription, never for the traffic law of a particular country.
Comparison of European road signs
Wikipedia · retrieved 2026-08-23
Tertiary reference, cited for the conventional description of a mark, its usual name and where it is encountered. Where an issuing body defines the mark, that body is cited alongside and governs.
Manual on Uniform Traffic Control Devices
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what a sign depicts, which countries use which variant, and the broad regulatory lineage — not for an article number of the treaty or for the law of any single jurisdiction.
Manual on Uniform Traffic Control Devices for Streets and Highways
Federal Highway Administration · retrieved 2026-08-23
The United States traffic sign standard, published openly. The MUTCD's word-led signs are a deliberate departure from the pictogram-led Vienna Convention used across Europe, and the records say which system they describe.

Last reviewed 2026-08-23

Part of

Road signs across national systems

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Meanings

Officially standardisedVerified fact

Requires traffic in both directions to stop while a school bus is loading, deployed as a hinged octagonal sign on the bus's side.

Contexts: Road signage

Officially standardisedVerified fact

Is among the few cases in which a vehicle rather than the highway authority displays a legally binding traffic control device.

Contexts: Road signage

Confidence

IdentityHigh confidence: High confidence because the identity is documented in encyclopedic references, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

Convention on Road Signs and Signals (Vienna, 8 November 1968), consolidated text
United Nations Economic Commission for Europe · retrieved 2026-07-31
A treaty binding only on its contracting parties. It prescribes sign categories, shapes and colours and permits national variants within them; it does not describe the signage of non-signatory states, notably the United States. Cited for category and design prescription, never for the traffic law of a particular country.
Comparison of European road signs
Wikipedia · retrieved 2026-08-23
Tertiary reference, cited for the conventional description of a mark, its usual name and where it is encountered. Where an issuing body defines the mark, that body is cited alongside and governs.
Manual on Uniform Traffic Control Devices
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what a sign depicts, which countries use which variant, and the broad regulatory lineage — not for an article number of the treaty or for the law of any single jurisdiction.
Manual on Uniform Traffic Control Devices for Streets and Highways
Federal Highway Administration · retrieved 2026-08-23
The United States traffic sign standard, published openly. The MUTCD's word-led signs are a deliberate departure from the pictogram-led Vienna Convention used across Europe, and the records say which system they describe.

Last reviewed 2026-08-23