Interstate route sign
A red, white and blue shield with a route number. It marks a road in the Interstate Highway System.
Rules vary by state and country. This explains the sign's standard meaning in the U.S. Manual on Uniform Traffic Control Devices; it isn't legal advice.
How to read it
The MUTCD sets its design: a cutout shield with the number in white on blue, the word INTERSTATE in white on red, and a white border, sometimes with the state's name. Interstate numbers are assigned by the American Association of State Highway and Transportation Officials on the states' recommendations.
Also searched as: interstate shield.
Reading the number
The number carries information, as Pennsylvania's manual explains. One- and two-digit even numbers generally run east–west, rising from I-10 in the south to I-94 in the north; odd numbers generally run north–south, rising from I-5 on the West Coast to I-95 on the East. A three-digit number beginning with an even digit usually connects to Interstates at both ends, often as a loop; one beginning with an odd digit is usually a spur, connected at one end.
More road signs
Sources
- MUTCD 2009 Edition, Chapter 2D: Guide Signs for Conventional Roads, MUTCD 2009, Part 2, U.S. Federal Highway Administration, Sections 2D.09, 2D.11
- Pennsylvania Driver's Manual, Chapter 2: Signals, Signs and Pavement Markings, Pennsylvania Department of Transportation, p. 20
- Official Florida Driver License Handbook, rev. 08/2023, Florida Department of Highway Safety and Motor Vehicles, p. 47
- The Evolution of MUTCD, Updated December 2023; after H. Gene Hawkins, Jr., ITE Journal, 1991–1994, U.S. Federal Highway Administration, Part I, 1961 Fourth Edition
Last reviewed September 25, 2026 by Rory Hansen. How we research