Interstate Route Marker — Meaning
- Category
- Guide
- Shape
- Shield
- Colors
- Blue, Red, White
- Text
- I-[number]
- MUTCD Code
- M1-1
What does the Interstate Route Marker mean?
The Interstate Route Marker is the iconic blue and red "shield" with white interstate number. It identifies routes within the federal Interstate Highway System. Even-numbered interstates run east-west; odd-numbered run north-south. Three-digit interstates are urban loops or spurs.
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1
Use to identify your current interstate
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2
Follow these signs to stay on your route
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3
Combine with directional signs (NORTH, SOUTH, EAST, WEST) for orientation
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On every interstate highway -
At every interstate entrance ramp -
On overhead direction signs -
On exit gore signs
Interstate numbering follows a logical system: even-numbered = east-west, odd-numbered = north-south. Lower numbers are in the south/west; higher numbers in the north/east.
Practice questions about the Interstate Route Marker
Test your knowledge with real DMV-style questions, each with the correct answer and explanation.
States that test this sign
The Interstate Route Marker appears in DMV practice tests for 10 states. Click any state to see its full DMV practice page.
How are interstate numbers assigned?
What is a 3-digit interstate?
Can bicycles or pedestrians use interstates?
Related signs
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