I found an interesting discussion (to me, at least, being a major roadgeek) on some random blog about how you refer to your local highways/freeways. They had a good discussion going too, until it died out and eventually got closed due to spam. What you call the freeways doesn't seem like that big of a deal until you give or get directions from someone from out of state. 
I've lived in SoCal most of my life, and of course, the vast majority of our freeways are referred to as "the [number]", such as the 60, the 5, and the 101 for CA 60, I-5, and US 101. Many freeways (usually closer to LA) are also called by name, which would make those numbers the Pomona Freeway, the Golden State/Santa Ana Freeway, and the Hollywood/Ventura Freeway, respectively. Pretty much the only qualification for getting a "the" is the fact that it's a freeway-standard road. State Routes on surface streets, such as Beach Blvd (SR 39) and Whittier Blvd (SR 72) are almost never referred to by number.
Of course, this is different from residents of No(r)Cal
p) and apparently the rest of the country, who refer to their freeways as "15", "40", or "80", with names and/or "I-[number]" also interchangeably used.
As stated in the blog, I would also like your opinions on where the "the" starts and stops, and whether it's used in any other part of the country, just to prove to ourselves that we're not crazy (even though we are).
I've lived in SoCal most of my life, and of course, the vast majority of our freeways are referred to as "the [number]", such as the 60, the 5, and the 101 for CA 60, I-5, and US 101. Many freeways (usually closer to LA) are also called by name, which would make those numbers the Pomona Freeway, the Golden State/Santa Ana Freeway, and the Hollywood/Ventura Freeway, respectively. Pretty much the only qualification for getting a "the" is the fact that it's a freeway-standard road. State Routes on surface streets, such as Beach Blvd (SR 39) and Whittier Blvd (SR 72) are almost never referred to by number.
Of course, this is different from residents of No(r)Cal
As stated in the blog, I would also like your opinions on where the "the" starts and stops, and whether it's used in any other part of the country, just to prove to ourselves that we're not crazy (even though we are).