Thanks to modern technology, we often take road signs throughout the country for granted. But there’s a lot that goes into the naming and labeling of each highway. With these explanations and fun facts, you’ll become a road warrior in no time.

Interstate Highways  

• Established under the Eisenhower administration, signs are marked with red-and-blue shields.
• Major highways are identified by one- and two-digit numbers.
• Routes that go north­ to south are assigned odd numbers, with the numbers growing larger from the west to the east.

Example: Interstate 5 runs through California, Oregon, and Washington, from the Mexican border to the Canadian border.

• Routes that go from the east to the west are assigned even numbers, with the numbers growing larger from the south to the north.

Example: Interstate 90 crosses the United States from Seattle, Washington, all    the way to Boston, Massachusetts.

US Highways

• US highways are labeled with black-and-white badge signs, and range from one to three digits.
• These highways follow the same odd-and-even method of interstates, but the numbers grow in opposite directions.

North-South: US Highway 1 runs from Maine to Florida.
East­-West: US Highway 82 runs from New Mexico to Georgia.

State and County Routes

• Signage for these routes differs based on each state and county.
• For the most part, states follow both the Interstate and US Highway patterns, assigning odd numbers to north-to-south routes and even numbers to east-to-west routes.

Fast Facts!

• It took 17 years to create, and fund the idea of the interstate.
• The states set the speed limits.
• The red-and-blue shields used to designate interstate signs are trademarked by the American Association of State Highway officials.
• There are no design rules dictating the shape of roads.
• No state has fewer than 3 interstates.