Interstates and US routes w/o a duplex within a state

[hotdogPi]

I-393.

Why? Triplexes aren't duplexes.

I could not find any other "entirely triplexed or more" US routes or Interstates within any state, but there might be more.

[Charles2]

I-85, 165 and 10 in Alabama made the cut. I-65 almost made it, but it has a short concurrency with US 82 in the Montgomery area.

I-759 in Gadsden also makes the cut.

[froggie]

Why? Triplexes aren't duplexes.

Semantics.  Also why "concurrency" is a better term to use.

[NE2]

"Overlap" is less awkward.

[pianocello]

I-235 in Iowa. (and if you want to argue semantics, I-129 is concurrent with US-20 and US-75 its entire length in the state)

Of all the US highways in Iowa, all of them have an overlap of some sort. Even the quarter mile of US-77 is concurrent with US 20 Biz.

[The High Plains Traveler]

Not including any 3dIs.

In Colorado, you only have the relatively trivial examples of U.S. 84, 138 and 350 as having no concurrencies. U.S. 350 ends at U.S. 160 near Trinidad.

In Arizona, neither I-8 nor I-19 have concurrencies. I think as it's been truncated, neither does U.S. 89.

In California, I-8, U.S. 6, U.S. 199, U.S. 101 (pretty sure about this).

Also U.S. 395.

[Thing 342]

IIRC, there are no US highways of any significant length (longer than 10 miles) that go without a concurrency in Virginia. As for interstates, the only ones without an overlap are I-295, I-664, I-464, I-564, I-195, and I-381.

[Eth]

In California, I-8, U.S. 6, U.S. 199, U.S. 101 (pretty sure about this).

Doesn't US 101 have a concurrency with CA 1 somewhere? I seem to recall having seen one signed somewhere west of L.A. GMaps shows one in Ventura, maybe it was there.


All Interstates in Georgia have hidden state routes running with them, but if you want to restrict it to signed routes only, that narrows it a little: I-24, I-59, I-95, I-185, I-475, I-520, and I-675 aren't signed alongside any other routes. US routes get blanked here, though, because they're also all paired with state routes, and those are all signed.

[The High Plains Traveler]

In California, I-8, U.S. 6, U.S. 199, U.S. 101 (pretty sure about this).

Doesn't US 101 have a concurrency with CA 1 somewhere? I seem to recall having seen one signed somewhere west of L.A. GMaps shows one in Ventura, maybe it was there.

Yes, but not with any U.S. or Interstate route. I thought this thread was only looking for those.

[Alex4897]

Delaware:

-I-495

aaaand that's it to my knowledge

[PHLBOS]

PA (off the top of my head)

I-95

I-95 has a short duplex with U.S. 322 between Exits 3 and 4.

Forgot about that.  I've since edited my earlier post to reflect such.

New Jersey:
...
I-287

Nope, there's a very short duplex with NJ 17 at the NY State line.

[SD Mapman]

SD: I-229... aaaand that's it.

[bzakharin]

New Jersey:

I-195
I-287
I-76

US 322?

How about I-278?

[PHLBOS]

New Jersey:
...
I-287

How about I-278?

For NJ, yes.

Maybe the above-287 is a typo for I-278 since (as mentioned earlier) I-287 has a short duplex w/NJ 17 at its northern end.

[odditude]

New Jersey:

I-195
I-287
I-76

US 322?

Until the construction's done, I-76's eastern terminus is on a multiplex with I-295.

North of where US 322 splits off of the Black Horse Pike (which continues NB as NJ-42), it's concurrent with CR 536.

[OCGuy81]

In California, I-8, U.S. 6, U.S. 199, U.S. 101 (pretty sure about this).

California seems to have quite a few that run solo in the state.

A few more that come to mind...

I-15
I-215
I-405
I-605
I-105
I-110
I-710
I-805
US 6

[hbelkins]

In Pennsylvania's case, now that I-279 has been truncated, where does it have another route along for the ride? The section that was concurrent with US 22 and US 30 is now part of I-376.

[NE2]

In Pennsylvania's case, now that I-279 has been truncated, where does it have another route along for the ride?

US 19 Truck.

[TEG24601]

I can only think of I-405, I-705, and I-205 in Washington.

[corco]

I can only think of I-405, I-705, and I-205 in Washington.

I
I 405 has a short concurrency with SR 900.

[TheStranger]

In California, I-8, U.S. 6, U.S. 199, U.S. 101 (pretty sure about this).

Doesn't US 101 have a concurrency with CA 1 somewhere? I seem to recall having seen one signed somewhere west of L.A. GMaps shows one in Ventura, maybe it was there.

Yes, but not with any U.S. or Interstate route. I thought this thread was only looking for those.

Looking at the posts on the first thread, it seems state route concurrencies also are being considered.  15, 215, 405 all have concurrencies with at least one state route, and 101 has quite a few.

Thus...the Interstate and US routes that completely lack overlapped routes in California:

I-105
I-205
I-505
I-605
I-805
future 905

I-8

I-110
I-710

I-380
I-780
I-980
I-238

US 6
US 199

EDIT: removed 210 as admtrap noted there is the concurrency with Route 2.

[hotdogPi]

I-8

From what I can tell, all of I-8 qualifies (both California and Arizona). Are there any other Interstates or US routes in more than one state where their entire length is not duplexed?

[Bickendan]

Oregon:
US 101 might be it, now that US 26 terminates at 101 instead of US 30 in Astoria. Let's see...

I-5 - OR 99, OR 99E, US 30
I-82 - US 395
I-84 - US 30, US 395
I-105 - OR 126
I-205 - OR 213, 224
I-405 - US 26, US 30

US 20 - OR 34, 99W, OR 99E, OR 126, US 97 Bus, US 395, US 26, OR 201
US 20 Bus (Toledo) - none
US 26 - I-405, US 97, US 20, OR 201
US 30 - I-405, I-5, I-84, OR 35*, US 197, US 395, OR 11, OR 7
US 30 Byp (Portland) - none
US 30 Bus (Huntington) - none
US 95 - none
US 95 Spur (Weiser ID) - none
US 97 - US 26
US 97 Bus (Klamath Falls) - OR 39 Bus, OR 39
US 97 Bus (Bend) - US 20
US 101 - none
US 101 Bus (Astoria) - OR 202
US 197 - US 30
US 199 - none
US 395 - OR 140, US 20, US 26, I-84, US 30, US 730, I-82
US 730 - US 395

None of the Interstates then, and US 95, 101 and 199 are the only mainline US highways that have no overlaps.
Bus 20 (Toledo), Bypass 30 (Portland), Bus 30 (Huntington), and Spur 95 (Weiser ID) also need some overlap love.

*Not that it affects US 30's qualification at all, but OR 35 is included if it terminates at I-84 or at the state line on the Hood River Bridge instead of at US 30.

[corco]

I-8

From what I can tell, all of I-8 qualifies (both California and Arizona). Are there any other Interstates or US routes in more than one state where their entire length is not duplexed?

US 163, US 195

[vtk]

Ohio has I-270, I-280, I-470, I-471, I-490, I-675.

West Virginia has US 30, US 22, I-470, I-79.

Indiana has I-275.  Kentucky has I-275 and I-471.