Highways that are entirely concurrent with another highway in a state

[jp the roadgeek]

Except for a brief 1/2 mile connection to I-84, CT 15 is entirely concurrent with US 5 from the north end of the Wilbur Cross Parkway. (and until 1980, was concurrent with the former I-86 to Sturbridge, MA; as well as with US 6 to Manchester, and then with US 44 from Manchester to Willington).

US 202 is concurrent with other routes for about half its journey through the state.  It is concurrent with US 6 as it enters the state, then joins a quadplex with I-84 and US 7, then leaves the quadplex with US 7.  After it leaves the US 7 concurrency a mile north of the I-84 split (it used to remain concurrent until the US 7 Brookfield bypass was completed), it runs alone and rejoins US 7 at the north end of the bypass and runs concurrent again to New Milford.  Then after an ever so brief concurrency with CT 67, it runs alone to Canton, then runs concurrent with other routes the rest of it's journey through CT (and to Westfield, MA); first with US 44, then with CT (and MA) 10.

US 6 is concurrent with I-84 for 23 miles of its journey through the state: 5 miles in Danbury, 4 miles from Newtown to Southbury, and 14 miles from Farmington to Manchester.

[thspfc]

I don't know of any in Wisconsin besides the obvious (and infamous) one, which is US and I-41.

[hotdogPi]

I don't know of any in Wisconsin besides the obvious (and infamous) one, which is US and I-41.

I-535

[TheHighwayMan3561]

I don't know of any in Wisconsin besides the obvious (and infamous) one, which is US and I-41.

894 qualifies.

[TheHighwayMan3561]

I don't know of any in Wisconsin besides the obvious (and infamous) one, which is US and I-41.

I-535

Technically no, because a small stub continues to 5th Avenue after US 53 leaves.

[kphoger]

I don't know of any in Wisconsin besides the obvious (and infamous) one, which is US and I-41.

I-535

Technically no, because a small stub continues to 5th Avenue after US 53 leaves.

Kinda like the southernmost portion of I-135 in Kansas, the only mileage not overlapped with I-81.

[thspfc]

I don't know of any in Wisconsin besides the obvious (and infamous) one, which is US and I-41.

I-535

Technically no, because a small stub continues to 5th Avenue after US 53 leaves.

894 qualifies

Oh mah goodness, three replies in the first two minutes of the post, that's a record. Anyways, 535 does not technically count since there's a .1 mile segment of it at its south end that is not concurrent with any other highway. As for 894, yes, not sure how I missed that one. It actually qualifies three times over - I-41 and US-41 for its whole length, and US-45 for half and I-43 for the other half.

[webny99]

Kinda like the southernmost portion of I-135 in Kansas, the only mileage not overlapped with US I-81.

FTFY.

[MikieTimT]

I-530 is entirely concurrent with US-65, until they officially extend to I-69 at Monticello, some decades into the future.

[Some one]

US 62/180 share a concurrency throughout New Mexico.

I-29 and US 81, with the exception of a short stretch, share a concurrency in ND.

[TheHighwayMan3561]

US 2/141 in Wisconsin between the Michigan sections
I-190 (SD) and US 16

[Great Lakes Roads]

I-129 (NE-IA) with U.S. 20 in the Sioux City area

[sbeaver44]

I-581 (VA) is concurrent with US 220 for its entire length

I-480 in Iowa is entirely concurrent with US 6

I-72 is entirely concurrent with US 36 in Missouri

I-88 is entirely concurrent with IL 110 in Illinois

I-277 is entirely concurrent with US 224 in Ohio

I-87 in North Carolina is currently entirely concurrent with US 64

I-26 in Tennessee is entirely concurrent with US 23

US 48 in Virginia is entirely concurrent with VA 55

I-393 in New Hampshire is entirely concurrent with US 4 and US 202

[kphoger]

I-88 is entirely concurrent with IL 110 in Illinois

IL-110 is a fake highway.   

[ilpt4u]

I-88 is entirely concurrent with IL 110 in Illinois

IL-110 is a fake highway.   

As is its MO-110 Counterpart

Tho if IL-336 were to be decomissioned, there actually would be independently signed segments of IL-110

IL and MO should have signed the CKC just with the CKC banner, similar to how the AotS is signed with the AotS banner in MO and IA (where it is signed at all). The 110 designation is overkill/unnecessary

[kphoger]

I-88 is entirely concurrent with IL 110 in Illinois

IL-110 is a fake highway.   

As is its MO-110 Counterpart

Tho if IL-336 were to be decomissioned, there actually would be independently signed segments of IL-110

IL and MO should have signed the CKC just with the CKC banner, similar to how the AotS is signed with the AotS banner in MO and IA (where it is signed at all). The 110 designation is overkill/unnecessary

At least MO-110 follows an actual corridor.  But nobody in their right mind would use the Illinois portion to get from Hannibal to Chicago.

[ilpt4u]

At least MO-110 follows an actual corridor.  But nobody in their right mind would use the Illinois portion to get from Hannibal to Chicago.

I-55 would have to be in AWFUL shape, probably Closed, for much consideration to follow the CKC between Hannibal and Chicago instead of I-72 to I-55

[bwana39]

I am not sure it still works this way, but in Texas and California both. There used to be state route numbers that identified the route; sort of an inventory number, that might but more often do not duplicate the signed route numbers.

The only time you would see these numbers is in DOT contracts and RFP's .

[SkyPesos]

Surprised this one hasn't got mentioned yet: I-74 in Ohio is entirely concurrent with US 52.

[JayhawkCO]

Shocked no one has mentioned I-25/US87 in Colorado (unless I missed it).

[US 89]

Shocked no one has mentioned I-25/US87 in Colorado (unless I missed it).

It's in the OP...

I-25/US 87 share a hidden concurrency throughout Colorado.

[JayhawkCO]

Shocked no one has mentioned I-25/US87 in Colorado (unless I missed it).

It's in the OP...

I-25/US 87 share a hidden concurrency throughout Colorado.

Ha. That's why. Just looked at responses. Silly me.  Then I'll submit WYO344 and WYO346 which are the two state highways that make up the tail ends of the US87 landslide area.

[oscar]

I am not sure it still works this way, but in Texas and California both. There used to be state route numbers that identified the route; sort of an inventory number, that might but more often do not duplicate the signed route numbers.

The only time you would see these numbers is in DOT contracts and RFP's .

You might have in mind, for California, situations like legislatively defined state route 51 in Sacramento, which is signed (per that legislation) only as I-80 Business Loop.

More trivially, the entirety of Alaska's unsigned Interstate network is concurrent with signed state routes, though not necessarily the ones you might expect. A-1 is concurrent with part of AK 2, and part of AK 1 (which is in turn partially concurrent with part of AK 4). A-2 is concurrent with another part of AK 2. A-3 is concurrent with another part of AK 1. All of A-4 is concurrent with all of AK 3.

[US 89]

In addition to the full US/GA overlaps mentioned upthread, there are plenty of state routes in Georgia that spend their entire lives concurrent with other routes. Those include (and I'm probably missing a couple):

SR 3 - entirely concurrent with US 19 or US 41
SR 7 - entirely concurrent with US 41 or US 341
SR 8 - entirely concurrent with US 78 or US 29
SR 14 - entirely concurrent with US 29 or SR 154
SR 35 - entirely concurrent with US 319
SR 50 - entirely concurrent with US 82
SR 89 - entirely concurrent with US 441
SR 365 - entirely concurrent with I-985, US 23, or US 123
SR 515 - entirely concurrent with GA 5, GA 2/US 76, or GA 17

I don't know enough Georgia highway history to know for sure, but SR 9 and SR 13 may well be former examples as they look to be old alignments of US 19 and US 23 where they aren't still concurrent.

[golden eagle]

US 278 in Mississippi is concurrent with all of MS 6, US 61 from Clarksdale to Leland, and US 82 from Leland to the Mississippi River.

I-555 is concurrent with US 63 on its entire route.