Fellas, there's a good reason there's no U.S. Highway 1 in California (but
there is a U.S. 101):
U.S. highway north-south routes have odd numbers, with numbers increasing
from east to west.
U.S. highway east-west routes have even numbers, with numbers increasing
from north to south.
U.S. highway east-west routes ending in 0 tend to be cross-country routes.
Three-digit U.S. routes contain the two digits of their parents routes, but
there is not an odd and even number system.

And while on the subject:
Interstate north-south routes have odd numbers, with numbers increasing
from west to east.
Interstate east-west routes have even numbers, with numbers increasing from
south to north.
Interstate highway routes have one- or two- digit numbers.
North-south interstates ending with a 5 and east-west interstates ending
with a 0 are typically major cross-country routes.
A three-digit interstate always ends with the two-digit number of the main
interstate it loops off from, except I-238.
Three-digit road numbers beginning with an even number are either beltways
that go around a city or freeways that go through a city.
Three-digit road numbers beginning with an odd number branch off the main
interstate.

Now back to the regularly scheduled Vanagon programming...