And come to think of it, that's exactly how Waze and Google Maps and Apple Maps turn-by-turn directions read to me. Do these programs use different dialects in Southern California?
I would use the definite article with a route on a transit system, though, for example to identify a bus line or (when in a city that has one) a subway: "I'll ride the 28 home" or "I commute on the 10".
"How do you get there?"
"Take 10."
"Take 10 what?"
I've been seeing this meme a lot more lately. For some reason, it seems to be in fashion to make fun of people from [Southern?] California in this way at the moment.
So I drive on I-5 or I-90.
If it's a spur, then I just use the number. From Redmond, I would get on 405 to go to Bellevue. When I drive from Sunnyvale to Palo Alto, it is usually fastest to take 101 unless it's rush hour.
This is the same where I now live in New England, as well. "495", "128", "Route 3", "Route 1", "The Mass Pike"
"I'll take 85"
"If you're going to LAX from Ventura, Take Route 101 to I-405." Alternativeley "US 101" could be used.