Maine has highways, routes, and a turnpike.
Highway: a divided road with multiple lanes (usually 2 or 3) in each direction, and no stop lights.
Route: 2 lanes, usually one in each direction, may have stoplights or stop signs occasionally, but meant for long, back country trips
Turnpike: A highway with tolls
New York has Highways, Expressways, Throughways,
Expressway: See Maine, Highway, but with more lanes
Highway: Like a Maine route, but with more lanes and more stoplights, and not usually back country
Throughway: See Maine, Highway.
Southern California has The Roads:
The 5, The 101, and The 405. I think they call them Freeways, which are really just Highways. Not sure about The Definite Article on it though...
Northern California has HIghways, Expressways, and Routes:
Route: See Maine, Route, but more curvy sometimes due to mountains
Highway: See Maine, Highway, but with more lanes
Expressway: A road with fewer exits/roads and fewer stop lights, but 2-4 lanes in each direction. The Lawrence Expressway has really long greens if you're going the main way, and they're nicely timed!