I10 111.2 MM

[CA_Traveler]

West of Phoenix on I10 there are several miles of MMs like 111.2, 111.4, etc. What is that all about?

[Gene_Ginny]

Having the markers at .2 mile marks helps emergency services find you, particularly if they are comming from the opposite direction. They know where they have to cross the median to get to you. Police, Fire, Rescue and tow truck drivers know the markers in their service areas even if AAA doesn't even know which country you are in.

[paulj]

My guess is a speedometer test section, such as these listed for Washington
http://www.rainierautosports.com/reference/odocheck.htm

But I couldn't find any such notification signs along this stretch of I10 (via GM Streetview).

[CA_Traveler]

These MM appear over about a 2 mile distance MM 111 and 112 and are on both sides of I10. There is no apparent reason for their existence that I've noticed. No culverts, bridges, etc and trust me this is not a populated area.

I don't recall this type of sign along interstates. There are exit signs like 1 1/2 miles and there are county signs like 45.21 etc.

[Hank_MI]

Mile markers every .2 miles are very common on interstates. Mostly around more populated areas. When you get away from the populated areas they go back to one every mile. In an emergency/accident you don't have to go very far to find a mile marker when calling 911.

Can't believe you've never seen them before.

[crabbin_cabin]

enblethen wrote:
Normally, this would indicate something like a culvert or bridge under the highway.

IIRC this is the correct answer - at least in AZ. Highway workers use then as reference points for needed work- and (heaven forbid) snow plows!!

[enblethen]

Normally, this would indicate something like a culvert or bridge under the highway.

[agesilaus]

I think that they are mainly so if you call for help for some reason, AAA or whatever. You can tell them where you are. The main problem with that is that when you call the motor clubs and tell them you are west bound on I-10 at mile marker 123.4 they don't seem to have the slightest idea where that is. They always insist on the nearest town even tho you don't have any idea where the nearest town is.

Maybe the emergency service people can use the MM.

BK

[Bumpyroad]

they used to have those for marking a mile to check odometer accuracy, etc. I hope they didn't mark the entire length of the IS in tenths of a mile. 🙂
bumpy

[Steeljag]

Tax dollars at work, or.....in case you want to get out and run!

[Francesca_Knowl]

CA Traveler wrote:
What is that all about?

It's about tenths of a mile...;)