A basic rundown of the Interstate Highway System:

• The official name is the 'Dwight D. Eisenhower National System of Interstate and Defense Highways.'
• Routes with odd #'s run north-south (ex. I-55).
• Routes with even #'s run east-west (ex. I-70).
• For north-south routes, the lowest #'s are in the west (ex. I-5), while the highest #'s are in the east (ex. I-95).
  
• For east-west routes, the lowest #'s are in the south (ex. I-10), while the highest #'s are in the north (ex. I-94).
  
• Spur Route - a short road forming a branch from a longer, bigger route; always has an odd # as its first digit (ex. I-380 connects Waterloo & Cedar Rapids w/I-80 in Iowa).
  
• Bypass - a road or highway that 'bypasses' a built-up area of a town or city; always has an even # as its first digit (ex. I-215 travels part of the perimeter of Salt Lake City in Utah).
  
• Beltway - completely surrounds a metropolitan city, and it is often connected with multiple junctions to other routes; unlike other auxiliary Interstate Highways, beltways do not have termini; always has an even # as its first digit (ex. I-465 surrounds Indianapolis).

Just follow these rules & ya'll never get lost (at least, in a car). HEY!!!