the best explanation of interstate numbering i've read thus far

For those who've wondered why the interstates are numbered like they are, here's an explanytion from writer Harmon Jolley in Tennessee:

Most of the routes of the Interstate Highway System were assigned two-digit codes ending in zero (east-west highways) and five (north-south). Roads that run diagonally were given the other numbers. The higher-numbered Interstate routes are in the east and north, to avoid confusion with the U.S. Highway numbering scheme. The connecting routes into cities were given a three-digit code beginning with “one.” Bypass routes around cities were given other three-digit numbers that usually include the route being bypassed (such as I-285 around Atlanta). Interstate 24 runs diagonally, so it was given a diagonal route number.