Route number shield

A shaped outline whose form identifies the road network.

Also known as: Interstate shield, Highway marker

Road & transportStandard profile

Meanings

In the United States a route number sits inside a shield whose shape names the network: a shield outline for interstates, a circle for US highways, and a different shape in every state for state routes. The shape carries the network and the number carries the road.

Officially standardisedVerified fact
Identifies which network a numbered route belongs to by the shape of the marker enclosing its number.
Contexts: Road signage
Officially standardisedVerified fact
Uses a state-specific outline for state routes, so the same number in two states appears in two different shapes.
Contexts: Road signage
Officially standardisedVerified fact
Contrasts with European practice, where a route's class is carried by the sign's background colour rather than by a marker shape.
Contexts: Road signage

Visual description

A shaped outline — a shield, a circle or a state silhouette — containing a route number in contrasting colour.

Symmetry: vertical
Orientation: upright
Colours: blue, 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

Identifies which network a numbered route belongs to by the shape of the marker enclosing its number.

Contexts: Road signage

Officially standardisedVerified fact

Uses a state-specific outline for state routes, so the same number in two states appears in two different shapes.

Contexts: Road signage

Officially standardisedVerified fact

Contrasts with European practice, where a route's class is carried by the sign's background colour rather than by a marker shape.

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