What do odd-numbered highways indicate in terms of direction?

Odd-numbered highways are designed to primarily indicate north/south routes. This system is part of the United States highway numbering scheme, which uses odd numbers for highways that generally run vertically across the country, connecting locations from the northern states to southern states. For instance, Interstate 5 runs from the Canadian border in Washington down to the Mexican border in California, illustrating this concept well.

On the other hand, even-numbered highways correspond to east/west routes. Thus, the numbering system creates a structured way to understand which direction a highway is mainly oriented, aiding in navigation and planning for travelers.