[net.general] Interstate Highway numbering

dafa (09/17/82)

Circumferential interstate highways are assigned three digit route
numbers. The last two digits are the same as the interstate route
they connect to. But what is the significance of the first digit?

David Fay
ihuxu!dafa

spence (09/22/82)

#R:ihuxu:-11000:harpo:800015:000:92
harpo!spence    Sep 22 15:20:00 1982

Don't even numbered routes run east-west and odd numbered routes
North-South?

harp!spence

ser (09/23/82)

#R:ihuxu:-11000:harpo:800017:000:236
harpo!ser    Sep 23 08:53:00 1982

If I remember correctly, odd prefixes on three digit interstates indicate
"spurs", i.e., routes into or out of major cities, while even prefixes
indicate "circuits", i.e., routes around major cities.

						Steve Riegel
						harpo!ser