Interstate Route marker sign
Identifies an Interstate highway; used on all Interstate routes and in route sign assemblies on roads that meet them.
What to do
Use the route number and direction plaques to follow the Interstate.
Follow the route number together with the cardinal direction plaque (NORTH, SOUTH, EAST, WEST) above it to stay on the right Interstate.
Interstate and U.S. route numbers are assigned by AASHTO (2D.09). Number shown is an example.
Where it's used
Section 2D.11 requires the Interstate Route (M1-1) sign on all Interstate routes and in route sign assemblies on roads that meet them; Interstate and U.S. numbers are assigned by AASHTO (Section 2D.09). It is a cut-out shield with a red top band and white numbers on blue, at least 24 x 24 inches for one or two digits and 30 x 24 inches for three. In route assemblies an M1-1a version showing the State name may be used, and Interstate routes take first place (top or left) when routes share a road.
Don't confuse it with
- U.S. Route marker: The U.S. Route marker is a black-and-white shield, while the Interstate marker is red, white and blue.
- Off-Interstate Business Loop marker: The Business Loop shield has the Interstate shape but is green and white and leads off the Interstate through a town.
- State Route marker: State route markers are designed by each State and are often a circle or the State outline.
- Type
- Route markers
- Shape
- Shield
- Colors
- red, white, blue
- MUTCD code
- M1-1
- MUTCD section
- 2D.11
On state permit tests
Our questions for 3 states ask about this sign, including Washington DC, Rhode Island and Wisconsin.
Test yourself
What does the Interstate route marker look like? (Washington DC practice test)
- A white rectangle
- A yellow diamond
- A shield, red on top with INTERSTATE and blue on the bottom with the number
- A green circle
Show answer
A shield, red on top with INTERSTATE and blue on the bottom with the number. Interstate markers are shields with INTERSTATE in white on red at the top and the route number in white on blue below.
What does this sign mean? (Rhode Island practice test)
- Toll road
- U.S. route
- Interstate route marker
- State route
Show answer
Interstate route marker. The red, white and blue shield marks an Interstate route.
More route markers
Off-Interstate Business Loop marker
U.S. Route marker
State Route marker
County Route markerFrom the Manual on Uniform Traffic Control Devices (MUTCD), 11th edition, section 2D.11. Sign image: public domain, source.