US Highway Naming Convention

Atleast 10 might have asked this question to me.How do you find out whether a highway is running east-west or north-south?. Well the answers are here.

The procedure for naming the highways is US is systematic and followed some rules Major routes are designated by single or two digit numbers. If a route runs north-south, it is given an odd number, and if a route runs east-west, an even number. For north-south routes, numbering conventions begin in the west. Thus I-5 runs north and south along the West Coast, while I-95 runs north and south along the East Coast. For east-west routes, numbers begin in the south.Major routes usually traverse cities and are the shortest and most direct line of travel. Connecting interstate routes that travel around a city carry three-digit numbers.The interstate system totals 46,300 miles. All interstate highways are marked by blue signs with red tops.

U.S routes also follow a systematic naming.The north-south routes have odd numbers, with 1 to 3 digits. These numbers increase from east to west (just the opposite of the interstate system). For example, U.S. 1 runs along the East Coast (starts at Key West) and U.S. 101 runs along the West Coast.The east-west routes have even numbers, with 1 to 3 digits. The lowest numbers are in the North and increase moving south (just the opposite of the interstates). For example, U.S. 2 runs along the Canadian border; U.S. 90 runs through Texas.U.S. routes are posted in black letters on white signs.

Three highways run from coast to coast: I-10, I-80, and I-90.Seven highways run from border to border: I-5, I-15, I-35, I-55, I-65, I-75, and I-95.