[hx87]

Using single digit numbers by themselves to denote highways is awkward and confusing, but it's much less of a problem with double and triple digit numbers--"I took 95 from Boston to Washington" sounds prettier than "I took 5 from Seattle to Portland". Since the IHS numbering system starts from the southwest and increments up as you go northeast, southwestern Interstate highway numbers are disproportionately single-digit, which is probably why "the" is commonly prepended in SoCal.

[thanksforcoming]

Having grown up and Oregon and lived in Los Angeles for the past 7 years -- up north it would be "I took I-5 from Seattle to Portland" while in L.A. it would be "I took the 5 from Seattle to Portland." Neither dialect uses just the number on its own.

True for more than just single digit numbers too, e.g. I-205 vs. the 405.

[int_19h]

Here in WA, it seems that for single- and double-digit numbers, people usually prepend the prefix - so it's also I-5, not just 5; and I-90, not 90.

But for multi-digit, it's virtually never there - it's 405 and 520 (without "the"!), not I-405 and WA-520.

Now that I think about it, it's probably not so much about the number of digits, as it is about the number of words. So I-90 gets the prefix because "ninety" is a single word, but I-95 somehow sounds strange.

[spc476]

Up in Detroit (I have family there) almost everyone talks about 75 (I-75). Down here in South Florida (where I live), it's always I-95. Just "95" sounds strange to me, as well as "I-75".

I guess it's what you grew up listening to.

[ChuckMcM]

In the Bay Area, between those two, what I often hear is "I took 101 to San Francisco" or "101 was mobbed so I took 280" or "did you come down 85 or 280 to 101?" no 'i' no 'highway' no definite article.

[maxsilver]

In the Midwest, it's common to refer to short interstate numbers by the letter "I", as in "Drive I-96 until you get to Detroit" (pronounced as 'eye-ninety-six'). Which kind of solves that problem.

[sbuttgereit]

Except in LA, you are often times referring to roads that aren't part of the Interstate system. So, to drive where I use to live close to Beverly Hills to the small town of 'Montrose' (might just be a neighborhood actually) I would take the (I)10 to the (I)5 to the (State Route) 2, or if I had a stop in say, Glendale I'd take the (I)10 to the (I)5 to the (State Route) 134, make my stop get back on the (State Route) 134 to the (State Route) 2. You also had roads like the State Route 110 which turns into Interstate 110 at some point, etc.

To the driver these are just freeways. Now LA did have many more major freeways which were state routes and not Interstates (with the occasional US Highway, such as the 101) than most places do. Where I grew up in the mid-west, we really only had Interstates and regular roads and did say I80 and never, "the 80"