Only in these two states...

[cl94]

Michigan and Kansas: State route abbreviations are M- and K- instead of MI and KS

You forgot Utah.  State highways are still referred to as "U-10" or "U-229" - dating back from the days when the state highway badge was literally a letter U. 

I have a childhood memory of seeing SR ### used on a mileage sign in Utah.  Is that not the practice there?

Utah uses "SR-XX". "U-XX" is a roadgeek urban legend that has not been used by "normal people" in several decades.

But the original point remains incorrect because there is a third state (not Utah). Nebraska uses "N-XX", "L-XX", "S-XX", and "R-XX" for state highways, links, spurs, and recreation roads.

[US 89]

You forgot Utah.  State highways are still referred to as "U-10" or "U-229" - dating back from the days when the state highway badge was literally a letter U. 

I have a childhood memory of seeing SR ### used on a mileage sign in Utah.  Is that not the practice there?

Utah uses "SR-XX". "U-XX" is a roadgeek urban legend that has not been used by "normal people" in several decades.

Or "SR XX". I've noticed a trend in recent signage towards leaving out the dash after US and SR, but this is inconsistent and I'm not sure which is official now. Hell, even UDOT's own website is inconsistent.

You may still see a handful of straggler "U" signs such as on old street blades or forest service signage, but the "U" prefix has not been used since probably the 1960s or 1970s at the latest. (Note that the forest service sign linked above refers to a route segment that was decommissioned in 1969, so it's not like they were too interested in updating their sign content.)

[SkyPesos]

You forgot Utah.  State highways are still referred to as "U-10" or "U-229" - dating back from the days when the state highway badge was literally a letter U. 

I have a childhood memory of seeing SR ### used on a mileage sign in Utah.  Is that not the practice there?

Utah uses "SR-XX". "U-XX" is a roadgeek urban legend that has not been used by "normal people" in several decades.

Or "SR XX". I've noticed a trend in recent signage towards leaving out the dash after US and SR, but this is inconsistent and I'm not sure which is official now. Hell, even UDOT's own website is inconsistent.

You may still see a handful of straggler "U" signs such as on old street blades or forest service signage, but the "U" prefix has not been used since probably the 1960s or 1970s at the latest. (Note that the forest service sign linked above refers to a route segment that was decommissioned in 1969, so it's not like they were too interested in updating their sign content.)

On a related note, I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

[hotdogPi]

On a related note, I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

That's Texas and only Texas, unless you're counting Hawaii's Interstates where H is actually part of the designation.

[JayhawkCO]

I don't know how each state exactly call its state routes, but I've seen state abbreviations (CA, IL, etc), SR for State Route, SH for State Highway, C for Colorado, K for Kansas and M for Michigan.

I've never seen 'C' anywhere here.  Official or not. 

Chris

[Scott5114]

Michigan and Kansas: State route abbreviations are M- and K- instead of MI and KS

You forgot Utah.  State highways are still referred to as "U-10" or "U-229" - dating back from the days when the state highway badge was literally a letter U. 

I have a childhood memory of seeing SR ### used on a mileage sign in Utah.  Is that not the practice there?

Utah uses "SR-XX". "U-XX" is a roadgeek urban legend that has not been used by "normal people" in several decades.

But the original point remains incorrect because there is a third state (not Utah). Nebraska uses "N-XX", "L-XX", "S-XX", and "R-XX" for state highways, links, spurs, and recreation roads.

Nebraska highways are officially "Nebraska Highway X". "N-" is an abbreviation of this.

K- and M- are not officially abbreviations for anything–"K-32" is the entire name of the highway.

[SkyPesos]

I don't know how each state exactly call its state routes, but I've seen state abbreviations (CA, IL, etc), SR for State Route, SH for State Highway, C for Colorado, K for Kansas and M for Michigan.

I've never seen 'C' anywhere here.  Official or not. 

Chris

Probably exclusive to 470 then. That's the first place where I heard of the 'C'

[US 89]

^ Yeah, "C-470" is common usage both on signage (VMS in particular) and in common language, but that's really the only one. I've never seen or heard C-xx for any other state route in Colorado - always "SH xx" instead.

[oscar]

On a related note, I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

That's Texas and only Texas, unless you're counting Hawaii's Interstates where H is actually part of the designation.

If such an I- abbreviation were ever used in Hawaii (I doubt it ever has been), it would be "I-Hxxx" rather than "IH-xxx". Local preference would be to use the abbreviation "H-xxx" (in theory, per FHWA, "H-" is supposed to replace "I-" as the prefix, for Hawaii's Interstate subsystem). Or, better still, just use the route name rather than the number as is done with Hawaii's non-Interstate routes, considering that Hawaiians just aren't that into route numbers, and for a long time did without them.

[kphoger]

I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

Anywhere other than Texas??

[formulanone]

^ Yeah, "C-470" is common usage both on signage (VMS in particular) and in common language, but that's really the only one. I've never seen or heard C-xx for any other state route in Colorado - always "SH xx" instead.

I thought it was "E-470", because that's exactly what's on the signs. Are both in common usage?

[SkyPesos]

I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

Anywhere other than Texas??

Not "IH", but Ohio uses "IR" on its AADT tracker. Example:

[hotdogPi]

I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

Anywhere other than Texas??

Not "IH", but Ohio uses "IR" on its AADT tracker. Example:

Are you sure that's not Interstate Ramp?

[kphoger]

^ Yeah, "C-470" is common usage both on signage (VMS in particular) and in common language, but that's really the only one. I've never seen or heard C-xx for any other state route in Colorado - always "SH xx" instead.

I thought it was "E-470", because that's exactly what's on the signs. Are both in common usage?

E-470 is a tolled extension of C-470, and is administered by the E-470 Public Highway Authority agency/commission/sort-of-government-type-thing.

[kphoger]

I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

Anywhere other than Texas??

Not "IH", but Ohio uses "IR" on its AADT tracker. Example:

Are you sure that's not Interstate Ramp?

That's one heck of a busy ramp!

[hotdogPi]

I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

Anywhere other than Texas??

Not "IH", but Ohio uses "IR" on its AADT tracker. Example:

Are you sure that's not Interstate Ramp?

That's one heck of a busy ramp!

Looking at a map, it could refer to this ramp. It's mainline US 50.

[kphoger]

But yes, ODOT definitely uses that designation for mainline AADTs.

Here's another, more obvious example:

[SkyPesos]

I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

Anywhere other than Texas??

Not "IH", but Ohio uses "IR" on its AADT tracker. Example:

Are you sure that's not Interstate Ramp?

That's one heck of a busy ramp!

Looking at a map, it could refer to this ramp. It's mainline US 50.

The red circle is the location of the previous screenshot, which is not a ramp
For ramps, it'll mention that it's a ramp in "Direction:".

[skluth]

Wyoming and Illinois: Have a pointless I-180

Some may disagree about pointless, but this is my favorite

[kphoger]

CA and NM:  do not have a river border with Mexico

[kphoger]

I haven't looked at the pertinent laws in quite some time, so someone please correct me if I'm wrong:

OR and MO:  pedestrians not prohibited on Interstate highways.

(I'm not counting AK.)

[skluth]

CA and NM:  do not have a river border with Mexico

Neither do 46 other states. Only AZ and TX have a river border with Mexico.

[US 89]

^ Yeah, "C-470" is common usage both on signage (VMS in particular) and in common language, but that's really the only one. I've never seen or heard C-xx for any other state route in Colorado - always "SH xx" instead.

I thought it was "E-470", because that's exactly what's on the signs. Are both in common usage?

E-470 is a tolled extension of C-470, and is administered by the E-470 Public Highway Authority agency/commission/sort-of-government-type-thing.

Correct. C-470 specifically refers to the free southwest quadrant of the beltway, which is a regular state highway that runs from US 6 to I-25. E-470 is only the tolled beltway east of I-25.

[Revive 755]

On a related note, I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

That's Texas and only Texas, unless you're counting Hawaii's Interstates where H is actually part of the designation.

Could have sworn that I saw the IH abbreviation on a sign or message board in Wisconsin.

EDIT:

Florida and Indiana: A strict grid numbering system

I think they're also the only two states which officially use "State Road" instead of State Highway or State Route. Could be wrong about this, but I can't find the specific thread where we discussed how DOTs officially named their state inventory.

Mississippi also has a grid that's about as strict as Florida's, except for two (10 and 20) which were re-numbered for Interstates.

South Dakota also appears to have a grid numbering pattern.

[cl94]

On a related note, I've seen DOT documents abbreviate interstate highways as "IH XX" instead of "I-XX" before

That's Texas and only Texas, unless you're counting Hawaii's Interstates where H is actually part of the designation.

Could have sworn that I saw the IH abbreviation on a sign or message board in Wisconsin.

Wisconsin would call everything "highway X" with no prefix.