Interstates Adopting Mile/Exit Numbers Of Existing State/US Route

[swbrotha100]

So I-17, I-515 and I-580 in Nevada are some interstates that were built or numbered on top of existing state or US highways. They also adopted the mile markers and/or exit numbers of the previous route. Are there any other examples of this out there?

[Mapmikey]

I-585 in Spartanburg SC (US 176)

secret I-595 east of Washington DC (US 50)

For brief periods I-73/74 have retained the exit numbers of the US routes they overlay (US 74 and US 220) but do eventually convert over to the interstate mileage.

I don't believe I-17 fits your criteria...

Mike

[cl94]

I-86 took over everything from NY 17

[noelbotevera]

I don't believe I-17 fits your criteria...

Yes and no. The exit numbers are roughly a continuation of US 89's milemarkers north of  MM 200, and I-17 north of Camp Verde overlays US 89 in some places.

[roadman65]

I-335 in Kansas uses the preexisting Exit and mile markers for the Kansas Turnpike.

[Mapmikey]

I don't believe I-17 fits your criteria...

Yes and no. The exit numbers are roughly a continuation of US 89's milemarkers north of  MM 200, and I-17 north of Camp Verde overlays US 89 in some places.

US 89 and I-17 were never on the same roadway.

I-17 was built on top of AZ-69 and AZ-79.  It does appear that AZ-69 mile markers pickup from I-17's where it leaves Exit 262.  IIRC Arizona's mile markers are designated with respect to state boundaries even if the route doesn't start at one, so it is possible the I-17 north of AZ-69 uses the same mile markers that AZ-79 did (assuming back then mile markers were posted).

see https://www.arizonaroads.com/maps/1971-3.jpg

Mike

[swbrotha100]

I don't believe I-17 fits your criteria...

Yes and no. The exit numbers are roughly a continuation of US 89's milemarkers north of  MM 200, and I-17 north of Camp Verde overlays US 89 in some places.

US 89 and I-17 were never on the same roadway.

I-17 was built on top of AZ-69 and AZ-79.  It does appear that AZ-69 mile markers pickup from I-17's where it leaves Exit 262.  IIRC Arizona's mile markers are designated with respect to state boundaries even if the route doesn't start at one, so it is possible the I-17 north of AZ-69 uses the same mile markers that AZ-79 did (assuming back then mile markers were posted).

see https://www.arizonaroads.com/maps/1971-3.jpg

Mike

Sorry, I should have clarified my original post.

Yes, I-17 in Phoenix was built on top of old AZ 69. Instead of new mile markers (and exit numbers), I-17 kept the old numbering.

In Nevada, I-580 is cosigned with US 395, and I-515 is cosigned with US 93 and US 95. In those cases, the mile markers/exit numbers weren't redone for the interstate section. Maybe because they are 3di spurs.

[NE2]

I-278 on the Grand Central Parkway.

[cl94]

I-278 on the Grand Central Parkway.

Not anymore. It was renumbered.

[Big John]

I-41 using US 41 north of the Zoo Interchange

[cwf1701]

Unsigned I-296 in Grand Rapids (US-131).

[Brandon]

I-39 in Wisconsin.  North of Portage, it uses US-51's mile posting & exit numbering.

[froggie]

in the future, we may or may not see I-22 in Mississippi become an example of this.  hard to tell if MDOT will renumber US 78's exit numbers.

[SSOWorld]

ISHTA formerly had its own mile marker system which had the lowest number beginning at Chicago for each road with the exception of the Tri-State (which began its numbering at the south and went north.  Exit numbering (obviously) didn't exist at the time.  Now each has exit numbering overwritten based on the Interstate route assigned to it onto the tollway proper and exit numbers (as stated in other threads) have been/are being installed.

[english si]

I-11 in AZ.

[OCGuy81]

I-69 could prove interesting in this matter.

- Once completed in Indiana, will exits be renumbered?

- Does the portion signed in Kentucky use the Parkway's mileage?

- What about Texas?  Does, for example, 69E use US 77's mileage?

[Brandon]

I-69 could prove interesting in this matter.

- Once completed in Indiana, will exits be renumbered?

The exits north of Indianapolis already have been.  InDOT merely added 200 to each number, and will not renumber them after that.

[Mapmikey]

The exits north of Indianapolis already have been.  InDOT merely added 200 to each number, and will not renumber them after that.

This makes no sense.  If they aren't going to be accurate after I-69 is finished why did they renumber them at all?

Mike

[PurdueBill]

The exits north of Indianapolis already have been.  InDOT merely added 200 to each number, and will not renumber them after that.

This makes no sense.  If they aren't going to be accurate after I-69 is finished why did they renumber them at all?

Mike

200 is close enough, the overlap with 465 will keep 465's numbers (as it does with 74 today), and the number of people both traveling through on 69 from the southwest to the northeast around 465  with 69 AND keeping accurate track of the mileage is likely low.  A renumbering and another renumbering is silly when 200 is close enough and left vestiges of the old exit numbers in the new for ease of conversion for those affected.

[hbelkins]

I-69 could prove interesting in this matter.

- Does the portion signed in Kentucky use the Parkway's mileage?

No. The exit numbers on the WK Parkway were changed to reflect I-69 mileage. The Purchase Parkway exit numbers will remain the same, but the exits and mile markers on the WK were changed to reflect I-69's overlap mileage with I-24. That's why my brother texted me from the western end of the WK last year, asking why the exit number was 85 (just guessing) when he was 15 miles from the end of the parkway.

Interestingly enough, the WK's exit numbers did not change east of the Pennyrile, where I-69 now ends and will split off.

[roadfro]

In Nevada, I-580 is cosigned with US 395, and I-515 is cosigned with US 93 and US 95. In those cases, the mile markers/exit numbers weren't redone for the interstate section. Maybe because they are 3di spurs.

In both cases, the underlying US route (US 395 for I-580, US 95 for I-515) continues as a major freeway beyond the northern terminus of the Interstate. Renumbering the exits according to the Interstate mileage would have needlessly introduced an exit numbering gap on an otherwise seamless freeway.

With I-580, NDOT did install new mileposts according to revised I-580 mileage shortly after the route was signed. However, since Nevada restarts mileposts at county lines and the I-580/US 395 exit numbering is based on statewide mileage, the exit numbers were unaffected. (An slight exit number/statewide mileage continuity gap was probably introduced with the opening of I-580 between SR 431 and US 395 Alt since the new extension shortened the length of US 395. But I'm guessing NDOT thought it wouldn't be a big deal since there are no exits on the 580 extension and they probably didn't want to change all the exit numbers through Reno to the CA line.)

I-11 in AZ.

Yeah, not yet...and likely not ever. US 93 in Arizona, at least near the Nevada state line, is mileposted in the wrong direction for an Interstate–US 93 exit 2 is just before the Hoover Dam bridge, when mile 2 should be near Wickenburg according to standard mileposting methods.

[english si]

Yeah, not yet...and likely not ever. US 93 in Arizona, at least near the Nevada state line, is mileposted in the wrong direction for an Interstate–US 93 exit 2 is just before the Hoover Dam bridge, when mile 2 should be near Wickenburg according to standard mileposting methods.

Sure, it's back to front, but giving the two isolated interchanges (the one near Kingman having been given a number post the I-11 plan became official, AFAICS) US93 exit numbers despite the mileage system being US460's. Why would they have exit numbers at all, if it wasn't for the plan to be to extend the freeway and make a continuous route?

I can't imagine the first I-11 (non-future) signs not going up before the exit numbering is sorted out. Not least as the southern end is a slippery eel and that makes finding a zero point difficult!

[roadman65]

The exits north of Indianapolis already have been.  InDOT merely added 200 to each number, and will not renumber them after that.

This makes no sense.  If they aren't going to be accurate after I-69 is finished why did they renumber them at all?

Mike

Does anyone question I-70's mileage in Illinois where it is not accurate at all because it continues I-270's scheme from the Missouri State Line instead of its own mileage from the previous Poplar Street Bridge and now the new Mississippi River Crossing. 

[cpzilliacus]

Md. 200 continues to carry the exit numbers (and mileposts) from I-370.

[roadfro]

Yeah, not yet...and likely not ever. US 93 in Arizona, at least near the Nevada state line, is mileposted in the wrong direction for an Interstate–US 93 exit 2 is just before the Hoover Dam bridge, when mile 2 should be near Wickenburg according to standard mileposting methods.

Sure, it's back to front, but giving the two isolated interchanges (the one near Kingman having been given a number post the I-11 plan became official, AFAICS) US93 exit numbers despite the mileage system being US460's. Why would they have exit numbers at all, if it wasn't for the plan to be to extend the freeway and make a continuous route?

I can't imagine the first I-11 (non-future) signs not going up before the exit numbering is sorted out. Not least as the southern end is a slippery eel and that makes finding a zero point difficult!

The Kingman Wash Access Road exit had its number posted before I-11 was officially designated (the bypass project was completed in 2010, I-11 was designated with MAP-21 in 2012). I think the only reason there are exit numbers for either interchange on the Hoover Dam Bypass is because of the MUTCD requirement that all signage for freeway interchanges shall have exit numbers.

BTW: US 93 in Arizona (at least the northern independent segment) derives its milepost numbers from former US 466, not 460.