U.S. 93 Kingman to Hoover Dam

[ethanhopkin14]

This may have been addressed before, but last week I drove the section of U.S. 93 between Kingman and the Hoover Dam for the first time and I noticed the mileposts are signed so that the 0 milepost is at the dam in the northern section of the state rather than south to north.  I read that 93 has always been signed that way.  Is it signed that way on the I-40 to Wickenburg section too, or is it just the Kingman to the dam section?  And why is it signed like that?  Or is it just another of Arizona's weird milepost anomalies?  Makes for a weird section where there are two consecutive Exit 2s.  I did happen to see the future I-11 corridor sign, but I didn't get a picture.

[andy3175]

This may have been addressed before, but last week I drove the section of U.S. 93 between Kingman and the Hoover Dam for the first time and I noticed the mileposts are signed so that the 0 milepost is at the dam in the northern section of the state rather than south to north.  I read that 93 has always been signed that way.  Is it signed that way on the I-40 to Wickenburg section too, or is it just the Kingman to the dam section?  And why is it signed like that?  Or is it just another of Arizona's weird milepost anomalies?  Makes for a weird section where there are two consecutive Exit 2s.  I did happen to see the future I-11 corridor sign, but I didn't get a picture.

Speculatively, maybe it had something to do with US 466 preceding US 93 between the Dam and Kingman? But I don't really know why the mileposts increase from the Dam toward Kingman.

[roadfro]

I seem to recall reading somewhere that Arizona mileposts US highways and/or state highways from north to south (but still does interstates the standard south to north way). I haven't driven enough in Arizona to verify that.

When I first drove the new US 93 Hoover Dam Bypass alignment when it opened, I thought it was rather interesting to see that the first interchange on both sides of the AZ/NV state line is signed as exit 2.

[swbrotha100]

All 200 miles of US 93 in Arizona (Hoover Dam Bypass to Wickenburg) have the mileposts increase as you go north to south. It may have been inherited from old US 466. An ADOT employee once said that because US 93 enters Arizona on its western border, it justifies keeping the mileposts the way they are. If/when US 93 becomes I-11, maybe the mileposting will change then.

AFAIK all the other numbered highways in Arizona have mileposts that increase going northbound or eastbound (excluding parts of Loop 101 and Loop 202). Arizona has had a unique way of mileposting some numbered highways. See links below for why I-17 starts at mile 194 instead of mile 0:

https://www.arizonaroads.com/interstate/i17.html

http://www.interstate-guide.com/i-017.html

[ethanhopkin14]

All 200 miles of US 93 in Arizona (Hoover Dam Bypass to Wickenburg) have the mileposts increase as you go north to south. It may have been inherited from old US 466. An ADOT employee once said that because US 93 enters Arizona on its western border, it justifies keeping the mileposts the way they are. If/when US 93 becomes I-11, maybe the mileposting will change then.

AFAIK all the other numbered highways in Arizona have mileposts that increase going northbound or eastbound (excluding parts of Loop 101 and Loop 202). Arizona has had a unique way of mileposting some numbered highways. See links below for why I-17 starts at mile 194 instead of mile 0:

https://www.arizonaroads.com/interstate/i17.html

http://www.interstate-guide.com/i-017.html

Thanks, that helps clear that up.  I have known about the Interstate 17 mileposting abnormality for a long time, but I-17, I-19 (in km) and U.S. 93 are all "milepost challenged".  Are there any other odd mileposts inconsistencies in Arizona?

[roadfro]

All 200 miles of US 93 in Arizona (Hoover Dam Bypass to Wickenburg) have the mileposts increase as you go north to south. It may have been inherited from old US 466. An ADOT employee once said that because US 93 enters Arizona on its western border, it justifies keeping the mileposts the way they are. If/when US 93 becomes I-11, maybe the mileposting will change then.

AFAIK all the other numbered highways in Arizona have mileposts that increase going northbound or eastbound (excluding parts of Loop 101 and Loop 202). Arizona has had a unique way of mileposting some numbered highways. See links below for why I-17 starts at mile 194 instead of mile 0:

https://www.arizonaroads.com/interstate/i17.html

http://www.interstate-guide.com/i-017.html

I must have recalled incorrectly then. Thanks.

The US 466 explanation does make some sense. I always forget that US 466 preceded the extension of US 93 into Arizona on this alignment by a few years.

I-11 would probably necessitate some kind of change depending on ADOT's policy--I imagine at least the exit numbering would have to go in the proper direction. (For example, I-515 and I-580 in Nevada do follow the south-to-north milepost scheme, but have exit numbers based on the preexisting cosigned routes US 95 and US 395, respectively.)

[dfwmapper]

Loop 303 appears to be numbered as if it was an east/west highway descending from its eastern terminus at I-17. I-17 is exit 137, and that point is 137 miles east of the California border. The markers don't match up based on distance to the Mexican border.

[swbrotha100]

Loop 303 appears to be numbered as if it was an east/west highway descending from its eastern terminus at I-17. I-17 is exit 137, and that point is 137 miles east of the California border. The markers don't match up based on distance to the Mexican border.

ADOT added 100 to all the current mile markers on Loop 303 a few years ago. This was sometime before the stretch between Happy Valley Parkway and I-17 opened to traffic.

[dfwmapper]

I guess that makes the original numbering scheme based on a southern terminus at AZ 30, which is planned to cross Cotton Lane just south of current MC 85. If that's exit 0, then I-10 as exit 4 lines up.