Most routes on one road

[triplemultiplex]

I'll mention Wisconsin only to note that adding I-41 to the mix doubled our count of quadruple concurrencies.

[Henry]

Death Valley, NC says hello:


I-85 is now a Business Loop, and US 421 was also signed through here, but has since been rerouted onto the I-85 bypass further south.

[Super Mateo]

Here is the list of I-465 around Indianapolis.  I am going to use the SE Corner just north of the I-74 exit and north of the US 52 exit, since I think that has the most roads piggybacked.
I-465 (future I-69)
US 31, US 36, US 40, US 421, US 52
Indiana 67, Indiana 37
I don't think other than the interstates, no other roads are regularly posted on the loop.  You just have to follow the signs from the road that you were leaving, and hope that you catch the sign for the road that you wish to continue on the opposite side of the city.

You forgot I-74, which follows 465 around the south side. I believe it is currently the only route signed along the concurrence, until 69 is finished.

It wasn't forgotten.  I-74 isn't on the segment north of the US 52 exit.  I-74 and US 52 don't overlap anywhere on I-465.

[TheHighwayMan3561]

I can't think of anywhere in Minnesota larger than a quadruplex, which are partially unsigned in all cases.

[sparker]

In CA (pre-'64, of course) the record was 5 designations on one stretch of freeway: I-15, US 66, US 91, US 395, and CA 18 on the N-S freeway through central San Bernardino between the 5th Street entrance ramp (where US 66 "got on") to the East Highland Ave. exit, where CA 18 departed; a stretch of a little over a mile.  It got down to 4 when CA 18 was truncated at I-15 in 1961.  Tied for 2nd would have been the Pasadena Freeway (nee' Arroyo Seco Parkway) between the Four-Level and the Ave. 26/North Figureroa left exit in the Glassell Park section of L.A.; it carried US 6, US 66, US 99, and CA 11; all but US 66 departed at the Ave. 26 exit.  And, between 1959 and 1964 completed freeway sections of I-10 between Beaumont and Indio also carried US 60, US 70, and US 99.  Those "sign salads" were part of the rationale for the radical (and some may say horribly randomized) 1964 renumbering effort -- with the "one road/one number" sentiment prevailing within the Division of Highways at the time.   

US-40, US-50, CASR-160, CASR-16, US-99, CASR-70 were all carried by the W-X freeway in Sacramento at one point. I am not sure that all of the US-40 signs had disappeared when the I-80 signs showed up.

By the time the W-X freeway was completed in 1969, CA 70 ended (SB) at the corner of 3rd Street and Capitol Mall, the latter of which still carried US 40 and US 99W shields west of that street.  Wanting to get through traffic away from the Capitol, US 40 and CA 16 were rerouted down the 3rd Street/5th Street N-S (respectively) couplet; then turning east on Q Street, which was a couplet with P Street (WB).  US 40 then turned north on 16th Street as part of its couplet with the SB 15th Street; heading north and east out of town via the North Sacramento Freeway.  That alignment was created in 1965 and lasted until the W-X freeway was done and signed as I-80; at that time US 40 was superfluous (having been decommissioned 5 years earlier) and signage was removed; the single remaining old expressway portion of the SF-Sacramento route south of Davis was signed as "Temporary I-80" until the 1973 opening of the new I-80 facility, which included the interchange with CA 113 toward Woodland; that facility had lost its former US 99W signage the prior year when I-5 was completed north of Woodland toward Red Bluff.  But from 1963 to 1970 the freeway section from Davis to West Sacramento was "triple-signed" as I-80, US 40, and US 99W, regardless of the fact that the US routes were officially decommissioned back in 1964.  Also, about that time Temporary I-5 signs were applied to the original I-80 from the I-5 interchange area in Sacramento west over the Yolo Bypass to CA 113 and on CA 113 north to the I-5 crossing north of downtown Woodland, pending the opening of the I-5 version of the Yolo Bypass closely paralleling old CA 16; that viaduct was the final segment of I-5 to open between Sacramento and I-505.  I recall seeing the "TEMPORARY"-bannered I-5 shields sharing the I-80 reassurance masts circa 1969-70; those actually replaced the US 99W signage.  As far as US 40 shields west of Sacramento, most were gone by 1973 or so -- although a few stragglers remained around the segment between Vallejo and Fairfield until it was reconstructed in the mid-70's.   

[MNHighwayMan]

I can't think of anywhere in Minnesota larger than a quadruplex, which are partially unsigned in all cases.

And there's quite the theme between them:

I-94, US-52, US-59, MN-210
I-94, US-12, US-52, MN-55
I-94, US-10, US-12, US-52 (however briefly)
I-94, US-10, US-12, US-61

(Is there more than four? I can't think of any more than those.)

[Bitmapped]

For West Virginia, there are three 4-route multiplexes. All are in Randolph County:
US 33/US 48/US 250/WV 92 (Corridor H west of Elkins)
US 33/US 219/US 250/WV 92 (in Elkins)
US 219/US 250/WV 55/WV 92 (Elkins to Huttonsville)

[ilpt4u]

Among routes and systems plotted in TM, all of the 8's and the only 9 are on I-465 around Indianapolis.  The 9-route segment carries

Code Select Expand

I-465,I-69FutInd,US31,US36,US40,US52,IN37,IN67,US421

This assumes that "Future I-69" counts for purposes of this discussion.

Isn't I-74 on this segment, somewhere, as well? I guess that depends on which route I-69 takes, being North and West or South and East sides

[MNHighwayMan]

Among routes and systems plotted in TM, all of the 8's and the only 9 are on I-465 around Indianapolis.  The 9-route segment carries

Code Select Expand

I-465,I-69FutInd,US31,US36,US40,US52,IN37,IN67,US421
This assumes that "Future I-69" counts for purposes of this discussion.

Isn't I-74 on this segment, somewhere, as well? I guess that depends on which route I-69 takes, being North and West or South and East sides

No. That stretch (I-465 between exits 46 and 47, as I mentioned above) is just north of the eastern I-74 interchange. I-74 continues south and west from there.

[bob7374]

Death Valley, NC says hello:


I-85 is now a Business Loop, and US 421 was also signed through here, but has since been rerouted onto the I-85 bypass further south.

It will only be down to 4 routes once the Business 85 designation is dropped when the Greensboro Loop is complete around 2022. Sign plan for the future revised signage:

[mrcmc888]

Tennessee has many large multiplexes, due to their tendency to assign hidden state routes to each US route, as is common practice in southern states.  However, they're very inconsistent about signing them.  US routes may or may not be signed when they concur with an interstate, but don't expect to see a state route in a concurrency with anything other than another state route get signed, so most people driving on these don't realize how ridiculous the multiplexes actually are.  Including the hidden routes might be a little bit cheating, as it means that any concurrency with a US route involved will be at the very least a triplex, but I'm still including them.

Nashville has quite a few ridiculous multiplexes.  The James Robertson Parkway in Nashville carries US-31/41/431/unsigned SR-6/11.  Only the first three are signed, however.  The state routes are Tennessee's famous hidden designators.  Up ahead US-31 will split in two, but 31W continues on the multiplex while 31E goes its separate ways.  Interestingly, it's directly preceded by a brief hexaplex on 8th Avenue consisting of US-31/41/70S/unsigned SR-1/6/11, which then meets Broadway, which is yet another five-way consisting of US-70/70N (yes, a bannered route is concurring with its parent...only in Tennessee I guess)/431/unsigned SR-1/24.  70N and S have their west end at this intersection, but 431 will join 31 and 41 onto the Parkway.  70 and 24 continue east on Broadway.

Asheville Highway east of Knoxville briefly carries US-11E/25W/70/unsigned SR-9/signed SR-168.  25W and 9 are themselves coming off of a short triplex with I-40, following a longer triplex with I-640 north of town.  11 and 70 have a long triplex from the western outskirts of Knoxville all the way to downtown with unsigned SR-1 (Kingston Pike/Cumberland Ave/Magnolia Ave), which followed US-11W at the 11W/E split.  168 originates at US-129 north of Maryville and is signed for most of its solo route, but only the US routes are signed on this concurrency.

Northeast of Chattanooga at Cleveland, Tennessee, US-74 (which surprisingly ISN'T carrying a hidden state route with it) hops onto I-75 for a duplex.  In Ooltewah they are joined by US-11/64/unsigned SR-2, which began a triplex in downtown Cleveland.  Between exits 11 and 7B, I-75 carries five routes, but you would never know as none of the routes save for the interstate are signed.

The most famous multiplex, however, is the one of I-55/US-61/64/70/79 on the Memphis-Arkansas Bridge crossing the Mississippi.  As they enter Memphis, the US routes will leave the interstate to become Crump Boulevard, where they continue as a quintuplex for a short time with unsigned SR-1.  The bridge concurrency is not signed in the eastbound direction but is in the westbound, making it the largest concurrency that's signed in Tennessee.

https://www.google.com/maps/@35.1248174,-90.0672775,3a,75y,276.93h,85.94t/data=!3m6!1e1!3m4!1s7do-vrdZiDerK-6WFKfHog!2e0!7i13312!8i6656

[jp the roadgeek]

Wonder if there is a quadraplex in MA.  I can think of triplexes, like US 5/MA 10/MA 116 or MA 2/US 3/MA 16.  Probably is a four route one somewhere out east.

That's a good question.  Outside of silent concurrencies like 1/1A or 3/3A concurrent with other routes, I don't believe there are any in New England. 

1A/6/44/195 (RI)
4/9/107/202 (NH)
And many in Maine.

I-84/US 6/US 7/US 202 in Danbury, CT says hi.

Also I-95/US 1/US 9/US 46 for 1.16 mi. from the 1/9/46 exit to the center of the GWB. 


If you do count silent concurrencies, you have I-93/US 1 /MA 3/silent MA 1A/silent MA 3A from the Braintree split to the Sumner/Callahan tunnels.  You also have I-95/US 1/MA 128/silent MA 1A between Dedham and Canton. 

[hbelkins]

The most famous multiplex, however, is the one of I-55/US-61/64/70/79 on the Memphis-Arkansas Bridge crossing the Mississippi.  As they enter Memphis, the US routes will leave the interstate to become Crump Boulevard, where they continue as a quintuplex for a short time with unsigned SR-1.  The bridge concurrency is not signed in the eastbound direction but is in the westbound, making it the largest concurrency that's signed in Tennessee.

https://www.google.com/maps/@35.1248174,-90.0672775,3a,75y,276.93h,85.94t/data=!3m6!1e1!3m4!1s7do-vrdZiDerK-6WFKfHog!2e0!7i13312!8i6656

I've seen old maps that also show US 63 on that bridge and entering Tennessee.

[PHLBOS]

Wonder if there is a quadraplex in MA.  I can think of triplexes, like US 5/MA 10/MA 116 or MA 2/US 3/MA 16.  Probably is a four route one somewhere out east.

That's a good question.  Outside of silent concurrencies like 1/1A or 3/3A concurrent with other routes, I don't believe there are any in New England. 

1A/6/44/195 (RI)
4/9/107/202 (NH)
And many in Maine.

I-84/US 6/US 7/US 202 in Danbury, CT says hi.

Also I-95/US 1/US 9/US 46 for 1.16 mi. from the 1/9/46 exit to the center of the GWB.

True, but NJ isn't one of the New England states. Rothman, "1" and I were strictly talking about New England examples.

If you do count silent concurrencies, you have I-93/US 1 /MA 3/silent MA 1A/silent MA 3A from the Braintree split to the Sumner/Callahan tunnels.

Actually, MA 3A south exits off its parent at Neponset Circle (Exit 12) near Milton.  From there south to Braintree, it's simply I-93/US 1/MA 3/silent 1A along the Southeast Expressway.

[mrcmc888]

The most famous multiplex, however, is the one of I-55/US-61/64/70/79 on the Memphis-Arkansas Bridge crossing the Mississippi.  As they enter Memphis, the US routes will leave the interstate to become Crump Boulevard, where they continue as a quintuplex for a short time with unsigned SR-1.  The bridge concurrency is not signed in the eastbound direction but is in the westbound, making it the largest concurrency that's signed in Tennessee.

https://www.google.com/maps/@35.1248174,-90.0672775,3a,75y,276.93h,85.94t/data=!3m6!1e1!3m4!1s7do-vrdZiDerK-6WFKfHog!2e0!7i13312!8i6656

I've seen old maps that also show US 63 on that bridge and entering Tennessee.

That easily could be true.  I don't know where it would have been routed after going over the bridge, though.  Did it stay in West TN or dip right back into AR?

[hbelkins]

https://www.usends.com/63.html

[achilles765]

sorry for bumping a three year old post but I found this and wanted to offer as an example:
In Beaumont, Texas: Interstate 10/US 90/US 69/US 96?US 287.  Its a very short concurrency and only appears on one sign, but even once US 90 leaves at the next exit, the road still continues as Interstate 10/US69/US 96/US 287.

[bing101]

In CA (pre-'64, of course) the record was 5 designations on one stretch of freeway: I-15, US 66, US 91, US 395, and CA 18 on the N-S freeway through central San Bernardino between the 5th Street entrance ramp (where US 66 "got on") to the East Highland Ave. exit, where CA 18 departed; a stretch of a little over a mile.  It got down to 4 when CA 18 was truncated at I-15 in 1961.  Tied for 2nd would have been the Pasadena Freeway (nee' Arroyo Seco Parkway) between the Four-Level and the Ave. 26/North Figureroa left exit in the Glassell Park section of L.A.; it carried US 6, US 66, US 99, and CA 11; all but US 66 departed at the Ave. 26 exit.  And, between 1959 and 1964 completed freeway sections of I-10 between Beaumont and Indio also carried US 60, US 70, and US 99.  Those "sign salads" were part of the rationale for the radical (and some may say horribly randomized) 1964 renumbering effort -- with the "one road/one number" sentiment prevailing within the Division of Highways at the time.   

US-40, US-50, CASR-160, CASR-16, US-99, CASR-70 were all carried by the W-X freeway in Sacramento at one point. I am not sure that all of the US-40 signs had disappeared when the I-80 signs showed up.

I knew in places like Vallejo US-40, I-80 and I-5W were co-signed at the same time at one point until the renumbering removed US-40 and I-5W from what is now the Solano County section of I-80

https://www.aaroads.com/shields/show.php?image=CA19580801

https://www.aaroads.com/shields/show.php?image=CA19580171

[TheOneKEA]

Maryland has one four-route concurrency of I-595, US 50, US 301 and MD 2 in Annapolis. There is also a three-route concurrency of MD 16/313/404 in Denton, on the Eastern Shore.

[I-55]

Among routes and systems plotted in TM, all of the 8's and the only 9 are on I-465 around Indianapolis.  The 9-route segment carries

Code Select Expand

I-465,I-69FutInd,US31,US36,US40,US52,IN37,IN67,US421
This assumes that "Future I-69" counts for purposes of this discussion.

Isn't I-74 on this segment, somewhere, as well? I guess that depends on which route I-69 takes, being North and West or South and East sides

No. That stretch (I-465 between exits 46 and 47, as I mentioned above) is just north of the eastern I-74 interchange. I-74 continues south and west from there.

It never will actually be 9 though. Once I-69 is signed, IN-37 will be decommissioned between Bloomington and Fishers.

[wanderer2575]

For a variation, how about different routes along different segments of the same road (not multiplexed)?

In Michigan, Gratiot Avenue between Detroit and Port Huron carries parts of M-3, M-19, and BL I-94 on three separate segments.

[SkyPesos]

For a variation, how about different routes along different segments of the same road (not multiplexed)?

In Michigan, Gratiot Avenue between Detroit and Port Huron carries parts of M-3, M-19, and BL I-94 on three separate segments.

I-465 would be pretty much every route in the concurrency mentioned above, in addition to I-74. That'll be 9 routes.

Broad St in Columbus: US 40, US 62, OH 3, OH 16

3rd St/4th St pair in Columbus: US 23, US 33, US 62, OH 3

Detroit Ave in Cleveland: US 6, US 6 Alt, US 20, US 42, OH 3, OH 254

[Avalanchez71]

Tennessee has many large multiplexes, due to their tendency to assign hidden state routes to each US route, as is common practice in southern states.  However, they're very inconsistent about signing them.  US routes may or may not be signed when they concur with an interstate, but don't expect to see a state route in a concurrency with anything other than another state route get signed, so most people driving on these don't realize how ridiculous the multiplexes actually are.  Including the hidden routes might be a little bit cheating, as it means that any concurrency with a US route involved will be at the very least a triplex, but I'm still including them.

Nashville has quite a few ridiculous multiplexes.  The James Robertson Parkway in Nashville carries US-31/41/431/unsigned SR-6/11.  Only the first three are signed, however.  The state routes are Tennessee's famous hidden designators.  Up ahead US-31 will split in two, but 31W continues on the multiplex while 31E goes its separate ways.  Interestingly, it's directly preceded by a brief hexaplex on 8th Avenue consisting of US-31/41/70S/unsigned SR-1/6/11, which then meets Broadway, which is yet another five-way consisting of US-70/70N (yes, a bannered route is concurring with its parent...only in Tennessee I guess)/431/unsigned SR-1/24.  70N and S have their west end at this intersection, but 431 will join 31 and 41 onto the Parkway.  70 and 24 continue east on Broadway.

Asheville Highway east of Knoxville briefly carries US-11E/25W/70/unsigned SR-9/signed SR-168.  25W and 9 are themselves coming off of a short triplex with I-40, following a longer triplex with I-640 north of town.  11 and 70 have a long triplex from the western outskirts of Knoxville all the way to downtown with unsigned SR-1 (Kingston Pike/Cumberland Ave/Magnolia Ave), which followed US-11W at the 11W/E split.  168 originates at US-129 north of Maryville and is signed for most of its solo route, but only the US routes are signed on this concurrency.

Northeast of Chattanooga at Cleveland, Tennessee, US-74 (which surprisingly ISN'T carrying a hidden state route with it) hops onto I-75 for a duplex.  In Ooltewah they are joined by US-11/64/unsigned SR-2, which began a triplex in downtown Cleveland.  Between exits 11 and 7B, I-75 carries five routes, but you would never know as none of the routes save for the interstate are signed.

The most famous multiplex, however, is the one of I-55/US-61/64/70/79 on the Memphis-Arkansas Bridge crossing the Mississippi.  As they enter Memphis, the US routes will leave the interstate to become Crump Boulevard, where they continue as a quintuplex for a short time with unsigned SR-1.  The bridge concurrency is not signed in the eastbound direction but is in the westbound, making it the largest concurrency that's signed in Tennessee.

https://www.google.com/maps/@35.1248174,-90.0672775,3a,75y,276.93h,85.94t/data=!3m6!1e1!3m4!1s7do-vrdZiDerK-6WFKfHog!2e0!7i13312!8i6656

The concurrancy you speak of on 8th Ave actually is US 31/41/41A/70S.  Yes US 41 and US 41A run concurrent.

[kenarmy]

I-20, I-55, US 49, US 51 (unsigned), and MS 18 (unsigned) briefly share a concurrency. Further east,  I-20, I-59, US 80, US 11, and MS 19.

[ilpt4u]

Illinois currently has a 4-way concurrency in E St Louis, that used to be a 5-way

Currently: I-55/I-64/US 40/IL 3. Used to also have I-70, until the Stan Span opened and I-70 was routed off the PSB and its approaches