odd interstate routes run primarily north and south

You’re absolutely right! In the United States Interstate Highway System, routes with odd numbers run primarily north and south. Here’s why:

Numbering System: The Interstate numbering system is designed to be geographically intuitive. Odd-numbered routes generally run north and south, while even-numbered routes run east and west.

Starting Points: The lowest numbered Interstate routes (I-1 to I-20) tend to be located on the west coast and the east coast of the United States. As the numbers increase, the routes generally progress inland.