Washington

[FrCorySticha]

So, I just noticed last week when I went to Forks that SR 16 increases in milage from east to west, rather than west to east, as is standard. I know Oregon is weird with its non-interstates, but this is now the only one in Washington that, for whatever reason, does this. That I know of, anyway.

According to Wiki, SR 16 used to be SR/PSH 14 which ran north-south. I wonder if SR 16 just reused and extended the mile markers, since it runs pretty much northwest-southeast.

[Amaury]

That seems like a possibility, maybe. SR 505 is another one I noticed today. Increasing from north to south instead of south to north.

[stevashe]

That seems like a possibility, maybe. SR 505 is another one I noticed today. Increasing from north to south instead of south to north.

I suspect SR 505 is a similar case to SR 16 where the pre-1964 highway (SSH 1O in this case) ran east-west and the mile markers were maintained when the directions switched to north-south.

[Amaury]

Not an issue for SR 16, but for SR 505, I wonder if that's why Google Maps is erroneously referring to it as west-east. It's not a huge error that's going to get you lost or anything, but still. Even Wikipedia erroneously has west and east ends for the terminuses of SR 505 instead of north and south.

But when I look at it as a whole, SR 505 seems like it does run east and west more than north and south, so it could have been one of those oddities, where it's an odd number, but signed as east and west. Likewise, SR 16 could have maintained north and south signage, despite the even number. But that would be more something for a fictional thread.

[Amaury]

Not according to signage:
https://maps.app.goo.gl/dNxxe8tnHNkocmb99

https://maps.app.goo.gl/DVxKXHT74hcy96VX9

https://maps.app.goo.gl/mKLzAm238stLXYDg7

https://maps.app.goo.gl/7SRDrPciCtkAo6LH9

And I am aware that east-west = even and north-south = odd is not an absolute. I'm saying SR 505 could have been designated east-west, even with the odd-number since at its southern terminus, the milepost is 19 instead of 1 and vice-versa, but it's designated north-south. Likewise, SR 16 could have been designated north-south, even with the even numbering, but it's designated east-west.

[Bickendan]

Something to note here are the street addresses along these highways: They're pegged to their highway's mileposts, in an abxx format, where a is the mile, b is the 10th, and xx is building/door number within that 10th.
278424 US 101 would be milepost 278.4, second building within that 10th, and the four being the random final digit -or- the third address for that building (278420, 278422, 278424, etc. Think small office buildings or apartments that aren't using suite or apartment numbers).

Local or county variances might supersede this overall system, however, and opt for a more traditional 20 'blocks' per mile from a 0 point.

[jay8g]

SR 16 is a weird case, since it does primarily run north-south rather than east-west. And then there's all of the 16X state routes that don't actually connect to SR 16, because SR 410's "grid number" (a made-up term) is also 16. I wonder if there was once some consideration of making the south part of SR 167 (the part that's finally being built now) along with all of SR 410 part of SR 16... that would kind of make sense on a map, but that would have required them to run SR 16 concurrent with I-5 for a while (which wasn't really done in the original state highway grid) and would imply they were already expecting US 410 to go away, so probably not, but it's interesting to think about.