Should Route Number Duplication be Used by a Given State?

[florida]

It's done down here, but the duplicates are not next to each other (instead, they are plenty of miles away from each other), except in a couple of instances:

It depends on the state and how many routes they decide to sign. Out west, it's not likely to happen because there is so many sparse areas compared to the bigger states back east.

[PAHighways]

All duplicates were renumbered. Instead, with PA 380 and PA 283, (dups to I-283 and I-380), they just gave a different internal number. Why they can't just resign PA 283 as PA 300 and PA 380 as PA 400 is beyond me.

PA 283 seems like a logical extension of I-283 and I-380 and PA 380 are at either ends of the state, so why bother.

[algorerhythms]

MD has a rather blatant example: the exits for I-68 and MD 68 on I-70 are only about ten miles apart. The State Highway Administration installed signs on I-70 at the MD 68 exit to warn drivers that it's not the exit for I-68. I suppose that was less expensive than renumbering MD 68 when I-68 received its number.

Maryland has a few others:  MD 70 and I-70; MD 97 and I-97; MD 270 and I-270; MD 495 and I-495.  There used to be a MD 95 but I think it's been decommissioned.  There is a MD 170, but I-170 of course is long gone.

True, though those are all farther away from each other. It's kind of interesting that MD avoided duplicating numbers between US routes and state highways (with a couple exceptions; MD 222 is a former section of US 222, and MD 219 is the Oakland bypass, which if ever completed would become part of US 219), yet there are so many Interstate highway duplications.

[treichard]

PA did a  round of state route renumbering in the 1960s to get rid of all the duplicated numbers from the new Interstate highways.   They even had a loose rule for what the new numbers were for those routes.
http://www.m-plex.com/roads/numberi.html

More Interstate numbers were assigned later, but PennDOH chose not to renumber all the same-numbered state highways.  PA 380 survived  because there was no I-380 then and so there was no need to renumber PA 380.  Instead, there was I-81E or I-81S where I-380 is today.

The second instance of PA 283 was bypassed with the present I-283, which was then extended to Lancaster as PA 283. So that's a T-shaped highway signed as 283, not  discontinuous pieces.

=======

In 1925, PA laid out a primitive numbering system for its state highway network, just to have it messed up by the US Highways in 1926.  PA had to try again in 1928, and they removed the duplicated routes. This led to a few anomalies, such as the presence of US 22 causing PA 22 to become PA 29, a rule-breaking odd number on a north-south route, and three-digit numbers like PA 115 taking over the role of parent routes like PA 15 when three-digit numbers were normally given to child and spur routes instead.
http://www.m-plex.com/roads/numberus.html

========

The order of Maryland's numbering systems were:
US Highways first
State highways next
Interstate highways later

So there was never much conflict between state and US numbers.  MD 48 was decommissioned long before US 48 arrived as present I-68. 

[vdeane]

NY is another example of a state that avoids US/state number duplication (with the exception of US 2/NY 2) but has many interstate duplications (NY 90 being the most infamous; I think it would be amusing if an interchange was built to it from I-90).

[froggie]

With four exceptions (three of which are arguable), MnDOT strictly avoids duplication between Interstate, U.S., and state routes.

- MN 169 could be argued, since it's a state-designated extension of US 169.

- Same thing with MN 65, which is a state-designated extension of US 65, though US 65 has since been truncated from Minneapolis to Albert Lea.

- Also the same thing with MN 61, though this one is a bit murkier.  MnDOT truncated US 61 back to Wyoming ca. 1991, but they kept the stretch north of Duluth as a state route instead of a US route.

- The only one that is clearly a duplication is MN 62.  MN 62 #2 (the original existed 1920-1933) is in southwestern Minnesota, running from US 59 in Fulda to US 71/MN 60 in Windom.  In 1988, the former Hennepin CSAH 62 freeway was transferred to the state.  Because of local familiarity with the 62 route number, and what was deemed a low probability of confusion between the two MN 62 routes, MnDOT designated this freeway as MN 62 (#3).


Now where Minnesota DOES have a good bit of duplication is between I/US/MN routes and county routes.  One of the more prominent is where I-35 has an interchange with Freeborn CSAH 35 at Exit 22.

[hbelkins]

Kentucky only really has one duplication, that being US 79 and KY 79. And it could reasonably be argued that KY 79 is an extension of US 79.

While it's true that US 52 does enter the state, running along the US 119 route that dances in and out of Pike County along the West Virginia border, Kentucky really doesn't recognize US 52 as entering the state because this route is maintained by West Virginia. i don't think Kentucky actually acknowledges it as a Kentucky segment of US 119.

And then there's Tennessee, where there's no problem duplicating state route numbers with US or interstate numbers. All the US routes carry hidden state route designations, so in reality the US routes are only signed as such and are internally referred to by their state route numbers. But there is duplication between the state route numbers and interstate routes, and AFAIK the interstates don't carry any kind of state route designation (secret or otherwise).

[wytout]

CT has no duplications, and I believe MA has only one. MA 3 and US 3, but MA 3 is a southward continuation of US3 at it's southern terminus.  They really are the same road, not two different roads within MA borders.

[njroadhorse]

The only form of duplication the state of New Jersey has is in the 600-series county routes, which are duplicated, but are in different counties.

[WNYroadgeek]

NY is another example of a state that avoids US/state number duplication (with the exception of US 2/NY 2) but has many interstate duplications (NY 90 being the most infamous; I think it would be amusing if an interchange was built to it from I-90).

Don't forget NY 15 and US 15 (at least for now).

[Alps]

NY is another example of a state that avoids US/state number duplication (with the exception of US 2/NY 2) but has many interstate duplications (NY 90 being the most infamous; I think it would be amusing if an interchange was built to it from I-90).

Don't forget NY 15 and US 15 (at least for now).

NYS loves to continue its US and I- routes with state routes.  At least US/NY 2 are separate like I/NY 90 and I/NY 295.

[leifvanderwall]

I don't mind state duplication of routes but I would hope both routes are in good distance apart like in Michigan where I-94 in the lower southern part of the state and M-94 up in the Upper Peninsula. However US 24 and M-24 are not far enough apart and M-96 is a little too close to I-96. Oh well, it's not like anyone got lost or anything.

[vdeane]

Yeah, US 15/NY 15 really is an extension situation.  Even though NY 15 doesn't exist south of Wayland, as far as I know it's still signed all the way to US 15 (though I think I read that the situation changed recently).  In either case, once I-99 is put on the road, there won't be a duplication anymore.

I actually like the extensions.  US 2/NY 2 are due to US 2's short length in NY.  I-90/NY 90 is just insane.  The only thing preventing widespread confusion is that most locals think of I-90 only as the Thruway.

[treichard]

You might be surprised to hear that PennDOT's plan is to cosign I-99/US 15 (source: a reply from a PennDOT official to my inquiry on this very question, a few years ago).  It may be difficult for NYSDOT to fully remove US 15 in its state with AASHTO approval if PA does not. So NY should have both US 15 and NY 15 for the foreseeable future.

[mightyace]

You might be surprised to hear that PennDOT's plan is to cosign I-99/US 15

So, it looks like I-99 will be co-signed with something (US 220, US 322, PA 26, I-80, US 15) it's entire length!  (I am assuming here that I-99 stops at I-86/NY 17)

And, so I'm not totally off topic, I see that there is a PA 99 in NW PA running parallel to I-79.  (from Wikipedia http://en.wikipedia.org/wiki/Pennsylvania_Route_99)  According to Wiki, it has a different reference number (SR 0699).

I say let's keep that one and renumber the interstate.

[UptownRoadGeek]

The I-59 interchange along I-12 is only 20 miles from the interchange with LA-59.  Nobody seems to get them confused.  They are referred to as I-59 and LA-59 or Hwy 59 respectively.

[vdeane]

You might be surprised to hear that PennDOT's plan is to cosign I-99/US 15 (source: a reply from a PennDOT official to my inquiry on this very question, a few years ago).  It may be difficult for NYSDOT to fully remove US 15 in its state with AASHTO approval if PA does not. So NY should have both US 15 and NY 15 for the foreseeable future.

Why?  What's the point of having a road multiplexed for it's entire length?  IMO cases where a route is multiplexed for its entire length or at a terminus should be eliminated.

[njroadhorse]

You might be surprised to hear that PennDOT's plan is to cosign I-99/US 15 (source: a reply from a PennDOT official to my inquiry on this very question, a few years ago).  It may be difficult for NYSDOT to fully remove US 15 in its state with AASHTO approval if PA does not. So NY should have both US 15 and NY 15 for the foreseeable future.

Why?  What's the point of having a road multiplexed for it's entire length?  IMO cases where a route is multiplexed for its entire length or at a terminus should be eliminated.

Well, that could go either way for US 15 because it does terminate at Painted Post, NY, along with where I-99 is proposed to end.  You could curb it back to Williamsport where 15 and 99 meet, or keep it multiplexed since they'll end at the same point anyway.

[Roadgeek Adam]

Well, in thought, where would terminate US 15 back to? Williamsport? AASHTO would be better off just re-extending US 15 up to terminate in Rochester again, but that won't happen. We have the choice that US 15 can serve as the alignment it runs on currently and let 99 be on its own in NY, by diverting US 15 off at Lawrenceville, effectively terminating PA 287 at Lawrenceville and effectively decommissioning PA 1015 there at the state line

[hbelkins]

Well, that could go either way for US 15 because it does terminate at Painted Post, NY, along with where I-99 is proposed to end.  You could curb it back to Williamsport where 15 and 99 meet, or keep it multiplexed since they'll end at the same point anyway.

Isn't I-99 supposed to extend all the way north along I-390 to Rochester?

[hbelkins]

You might be surprised to hear that PennDOT's plan is to cosign I-99/US 15 (source: a reply from a PennDOT official to my inquiry on this very question, a few years ago).  It may be difficult for NYSDOT to fully remove US 15 in its state with AASHTO approval if PA does not. So NY should have both US 15 and NY 15 for the foreseeable future.

Why?  What's the point of having a road multiplexed for it's entire length?  IMO cases where a route is multiplexed for its entire length or at a terminus should be eliminated.

Former I-181 in Tennessee carried US 23 for its entire length. In fact, US 23 continued along the four-lane freeway even after I-181 had ended at both its northern and southern termini.

[froggie]

Isn't I-99 supposed to extend all the way north along I-390 to Rochester?

That's a theoretical, but nobody has ever posted anything official about it...

[Bryant5493]

Duplications don't bother me, but fragmented routes do. The only thing about duplications (Interstate and state routes) is that, if they're close in proximity, it can be killer in giving directions. S.R. 20 and I-20 cross one another in Conyers, Ga. At this point, S.R. 20 and S.R. 138 share pavement, so 138 is the highway given precedence here. Also, S.R. 85 and I-85 are close to one another, although they never meet. S.R. 85 is generally called "Highway 85" or "Ga. Hwy. 85."


Be well,

Bryant

[Darkchylde]

Louisiana generally doesn't duplicate US and state routes, with the exception of 63 (US 63 being a very late addition and LA 63 being nowhere near it). With the last major renumbering being in 1955, Interstate numbers are duplicated. However, with the exception of the LA 59/I-59 situation, the duplicate routes tend to sit far enough apart not to be "confusing."

[vdeane]

Well, in thought, where would terminate US 15 back to? Williamsport? AASHTO would be better off just re-extending US 15 up to terminate in Rochester again, but that won't happen. We have the choice that US 15 can serve as the alignment it runs on currently and let 99 be on its own in NY, by diverting US 15 off at Lawrenceville, effectively terminating PA 287 at Lawrenceville and effectively decommissioning PA 1015 there at the state line

I don't see what's wrong with terminating it at I-180 is Williamsport.  There's really no need for it to go on once I-99 is signed between there and Painted Post (which is itself way more minor than Williamsport is).