Which direction do 2-digit odd-numbered interstate highways primarily run?

• A. North-South
• B. East-West
• C. Diagonal
• D. Circular

Answer: (A)

Think about how the Interstate system is numbered. Odd numbers are assigned to routes that run primarily north–south, while even numbers run primarily east–west. Two-digit interstates are the main highways, so their direction follows this rule. You can see it with examples like I-5 along the West Coast and I-95 along the East Coast, both north–south corridors. Diagonal or circular patterns aren’t part of the standard numbering convention, so those options don’t fit the usual layout. So, two-digit odd-numbered interstates primarily run in a north–south direction.