Changes

Roads that circumscribe major metropolitan areas have three digits. Thus, 495 circumscribes the Boston area. The last two digits names (at least one of) the interstate(s) that this road stems from and connects to.

Roads Furthermore, three-digit interstates with a even first digit are ring roads that run north/south have odd numbersaround cities, like 495. Thus, 95 runs from Florida Odd first digits (like 395 in CT) signify a spur highway to Canadaa city.

Roads that run north/south have odd numbers and roads that run east/west have even numbers. Thus, [[Route 2]] 95 runs from CambridgeFlorida to Canada, out through Williamstownand Route 66 is perhaps the most famous example of an American east/west road. ''There are some caveats to this, however.'' Local parts of a north/south route may run east/west for relatively short spans, and beyondvice versa. And I-40 runs from Wilmington Even though Route 1 in Pennsylvania and New Jersey, for example, NCis odd numbered, to somewhere way out long stretches of it travel farther east/westthan north/south. (Even past Texas.)

It also helps to know that the numbers for interstate highways [http://www.ihoz.com/viol.html mostly] increase from west to east and south to north. Knowing this logic can (sort of) help you navigate when you are lost.