Do odd-numbered, 2-digit highways run north-south or east-west?

• A. East-West
• B. North-South
• C. Northeast-Southwest
• D. Circumferential

Answer: (B)

Odd two-digit highway numbers indicate a north-south route. In the highway numbering system, odd numbers are reserved for north-south corridors, while even numbers are used for east-west routes. This makes it easy to infer orientation just from the number: a highway with an odd two-digit number runs primarily north-south, as seen with routes that extend from the Canadian or Mexican borders up and down the country. The other directions don’t fit this rule because east-west routes use even numbers, and diagonal or circumferential routes aren’t part of the standard two-digit odd-even orientation scheme. So the correct orientation for odd-numbered, two-digit highways is north-south.