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  • Carrie Crocker

What is the Interstate Route Marker or Interstate Shield?

Interstate Shield

An interstate shield is a red, white, and blue shield that carries the word "Interstate" the state name, and route number ( It is the official route marker for the United States Interstate Highway System, trademarked by the American Association of State Highway and Transportation Officials.

The numbering system explained:

"Routes with odd numbers run north and south, while even numbered run east and west. For north-south routes, the lowest numbers begin in the west, while the lowest numbered east-west routes are in the south. By this method, Interstate Route 5 (I-5) runs north-south along the west coast, while I-10 lies east-west along the southern border ("


The planning for the “Dwight D. Eisenhower National System of Interstate and Defense Highways, also known as “The Interstate System”, started in the late 30’s.

It wasn't until President Eisenhower signed the Federal-Aid Highway Act of 1956 that the Interstate system needed its own brand of signs to differentiate it from U.S. state highway marker shields. (examples pictured below)

US State Highway Marker Shields

Image by Kurt Kohlstedt

After the signing of the Federal-Aid Highway Act of 1956, AASHTO (American Association of State Highway and Transportation Officials, referred to as AASHO in the 50's) commissioned designs for an interstate marker. A flood of 76 designs were sent from AASHTO's member states. Most traffic engineers went with a more practical approach to the sign design. A big letter “I” was the theme throughout the submissions, but some featured an eagle, a star, and even a huge map of the United States.

Following careful consideration, and after reviewing dozens of design proposals, a design was approved on August 14, 1957. The winning design was submitted by Texas traffic engineer, Robert Oliver. He picked a shield symbol as a sign of federal authority and submitted the design in black and white because he didn’t know colors were allowed. About ten years later, on September 19, 1967, Trademark Registration 835,635 was issued for the Interstate Shield.

Interstate Shield Design Proposals

Texas Interstate shield design submission

State submission: Texas - Image by Kenny Malone via

Interstate shield design submission

State submission: Unknown - Photo by Greg Castillo Photoshopped by Kenny Malone via

Interstate shield design submission

State submission: Unknown - At the time, the US had yet to add Hawaii and Alaska.

Image by Kenny Malone via

Florida Interstate shield design submission

State submission: Florida

Image by Kenny Malone via

Winning Interstate shield design submission

The winning Interstate Shield design by retired traffic engineer Richard Oliver of Texas. Image by Kenny Malone via

Official Interstate shield design

The official trademarked Interstate Shield we know today. The final design is a combination of the State of Missouri's and Richard Oliver's design.

Image by Kenny Malone via

Where Interstate Shields are Displayed.

On Reassurance Markers

Interstate Shield used on reassurance markers

On Highway Guide Signs

Interstate shield used on highway guide signs

On Mile Markers

interstate shield used on mile markers

On Highway Lanes

interstate shield used on highway lanes

Image by Federal Highway Administration via

How We Make Interstate Route Shields

  1. First, we digitally print the interstate shield graphic on to 3M Diamond Grade Reflective Sheeting.

  2. Next, the reflective sheeting is laminated using 3M ElectroCut Film 1170.

  3. After lamination, the graphic is cut out in order to be applied onto a metal blank.

  4. The graphic is either directly applied to a highway guide sign, or applied to a DOT-spec metal blank.

Interstate shield sign blanks

Buy and customize your own M1-1 on our online MUTCD store.

They ship in 3 business days or less!

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