Shortest duplex?

[bugo]

US 49 and 64 duplex for about 175 feet according to Google Maps.  Here is a view of the intersection.  They duplex long enough to cross the railroad tracks and that's it.

Are there any shorter duplexes?

[rickmastfan67]

That might be the shortest out there.  I know US-40 and PA-381 multiplex for about 217 ft per Google.
http://maps.google.com/maps?f=d&source=s_d&saddr=Farmington-Ohiopyle+Rd%2FPA-381+S&daddr=39.807061,-79.566261&geocode=FStoXwId1u1B-w%3B&hl=en&mra=mi&mrsp=1,0&sz=19&sll=39.807193,-79.565349&sspn=0.001508,0.003484&ie=UTF8&ll=39.806993,-79.565893&spn=0.001508,0.003484&z=19

[froggie]

VA 178 and VA 180, on Virginia's Eastern Shore, is 0.03mi per the VDOT traffic log.  Per VDOT's shapefiles, it measures out to 118.6ft centerline-to-centerline.

[Alex]

Florida 437 and 438 multiplex for 0.1 miles (a total of two blocks). This is the only section of SR 437 still in the state system; the rest is County or decommissioned.

http://www.southeastroads.com/florida400/fl-437_nb_fl-438_eb_after_merge.jpg

[Bryant5493]

Georgia State Routes 20 and 212 merge together shortly in Newton County, just south of the Rockdale County line. This duplex might be a tenth to two-tenths of a mile long.

S.R. 20/212 duplex


Be well,

Bryant

[TheStranger]

California's shortest (signed) concurrency can be found in Redding, at the west end of Route 44:

http://maps.google.com/maps?f=d&source=s_d&saddr=40.586696,-122.390195&daddr=Eureka+Way&hl=en&geocode=%3BFfZRawIdi3G0-A&mra=dme&mrcr=0&mrsp=0&sz=17&sll=40.586867,-122.391225&sspn=0.004172,0.006663&ie=UTF8&z=17

The shortest duplex that is not signed is Route 271 and Route 1 in Leggett, at 341 feet:

http://maps.google.com/maps?f=d&source=s_d&saddr=CA-1+S%2FCA-271+S&daddr=39.868131,-123.713543&hl=en&geocode=FTBXYAIdSEOg-A%3B&mra=mi&mrsp=1,0&sz=17&sll=39.868205,-123.714155&sspn=0.004216,0.006663&ie=UTF8&z=17

(Route 271 has an unsigned nine-mile concurrency with US 101 from Leggett north to Reynolds, at US 101 Exit 625)

[bulldog1979]

M-35 and CR 492 in Negaunee Township duplex to cross railroad tracks and skirt around a house, and M-35 yields the right of way to the county road in the process. According to MDOT's Physical Reference Finder, the duplex is between MPs 126.715—126.744 on M-35, making it a total of 0.029 miles, or 153 feet.

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Negaunee,+MI&sll=37.0625,-95.677068&sspn=64.409204,65.654297&ie=UTF8&hq=&hnear=Negaunee,+Marquette,+Michigan&ll=46.51226,-87.53372&spn=0.006977,0.008014&t=h&z=17

[froggie]

So far, looks like VA 178/180 still has "the title"...

[jdb1234]

US 31 and Shelby County 52 multiplex for roughly a block in Pelham.

[Mr. Matté]

CR 526 has two really short concurrences in its travels through Central Jersey:

• With NJ 33 in Robbinsville, officially .03 miles (158.4 ft), possibly less if traveling east
• With CRs 524 and 539 in Allentown, officially .02 mi (105.6 ft)

[Mr_Northside]

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Lycippus,+PA&sll=37.0625,-95.677068&sspn=49.089956,79.013672&ie=UTF8&hq=&hnear=Lycippus,+Pennsylvania&ll=40.229677,-79.430144&spn=0.005824,0.013733&t=h&z=17

In the tiny Western PA village of Lycippus, PA-982 and PA-130 duplex for just a couple of feet.  I suppose if the traffic volume warranted it, PennDOT could just make it a single-point intersection, but I doubt that will happen.

[Mapmikey]

VA 42 Bus and VA 257 might be slightly shorter than VA 178-180

Each direction of US 33 duplexes with US 11 NB in a way that looks in the ballpark of 100 ft or so.

Historically in Virginia it may be the original US 15-211 duplex in downtown Warrenton on Alexandria St between Main/Waterloo and Winchester St.  Shown as 0.01 in the traffic log and looks to be under 50 ft
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Warrenton,+VA&sll=37.0625,-95.677068&sspn=52.505328,90.175781&ie=UTF8&hq=&hnear=Warrenton,+Fauquier,+Virginia&ll=38.714175,-77.794932&spn=0.001595,0.002752&t=h&z=19

Mapmikey
Co-curator Virginia Hwys Project
www.vahighways.com

[RustyK]

What would the shortest Interstate duplex be?  I'd guess I-5 and I-10 in LA (about a mile or so from merge point to exit), or if you believe Google Maps, I-44 and I-55, also right around a mile, but I don't remember if 44 is technically a duplex with 55 right after the bridge in St. Louis.  Hard to imagine there are shorter, given the amount of space you'd need to get signage and leave room for merging, etc

[TheStranger]

What would the shortest Interstate duplex be?  I'd guess I-5 and I-10 in LA (about a mile or so from merge point to exit), or if you believe Google Maps, I-44 and I-55, also right around a mile, but I don't remember if 44 is technically a duplex with 55 right after the bridge in St. Louis.  Hard to imagine there are shorter, given the amount of space you'd need to get signage and leave room for merging, etc

I-87 and I-90 in Albany I think is the shortest, at 1/3 mile:

http://maps.google.com/maps?f=d&source=s_d&saddr=Unknown+road&daddr=42.696473,-73.842587&hl=en&geocode=FRiQiwIdpjWZ-w%3B&mra=dme&mrcr=0&mrsp=1&sz=15&sll=42.693792,-73.834949&sspn=0.020692,0.03283&ie=UTF8&z=15

[ATLRedSoxFan]

US 19 South and I-285 West come to mind as about 3/4 a mile and it's really not even signed except on GA 400, which says use Exit 4-something. Maybe it's just a link and not a true duplex.

[WNYroadgeek]

US 20A\NY 39 and NY 36 in Leicester is only 1/10 of a mile: http://maps.google.com/maps?f=d&daddr=42.696473,-73.842587&hl=en&geocode=FRiQiwIdpjWZ-w;&mra=dme&mrcr=0&mrsp=1&sz=15&sll=42.693792,-73.834949&sspn=0.020692,0.03283&z=15&um=1&ie=UTF-8&sa=N&tab=wl

[froggie]

What would the shortest Interstate duplex be?

It'd be a toss-up between the I-87/I-90 Albany example already mentioned and I-35E/I-94 in St. Paul, MN.  Depending on how you measure them, they both measure out to roughly the same...definitely within any margin-of-error.  Then there's which set of numbers you go by.  MnDOT officially considers the 35E/94 duplex is only 0.117 mile.  FHWA officially considers it 0.27 mile, but FHWA doesn't list the 87/90 duplex.  And NYSDOT (via their traffic log) even lists different mileages for the 87/90 duplex, depending on whether you're looking at the I-87 entry (0.54mi), or the I-90 entry (0.25mi).

[US71]

The shortest in Louisiana may be LA 2/US 71 near Hosston (1/2 mile)

http://maps.google.com/maps?f=d&source=s_d&saddr=US-71+N&daddr=LA-2+W%2FUS-71+S&geocode=FcDj9QEddodn-g%3BFajG9QEdeoZn-g&gl=us&hl=en&mra=ls&sll=32.886939,-93.875427&sspn=0.021695,0.032916&ie=UTF8&z=16

[froggie]

There's at least two shorter...per LaDOTD shapefiles, US 190/LA 434 in Lacombe is 1,697ft (0.32mi) and US 11/LA 433 in Slidell is 1,653ft (0.31mi).

[Duke87]

What would the shortest Interstate duplex be?

It'd be a toss-up between the I-87/I-90 Albany example already mentioned and I-35E/I-94 in St. Paul, MN.  Depending on how you measure them, they both measure out to roughly the same...definitely within any margin-of-error.  Then there's which set of numbers you go by.  MnDOT officially considers the 35E/94 duplex is only 0.117 mile.  FHWA officially considers it 0.27 mile, but FHWA doesn't list the 87/90 duplex.  And NYSDOT (via their traffic log) even lists different mileages for the 87/90 duplex, depending on whether you're looking at the I-87 entry (0.54mi), or the I-90 entry (0.25mi).

Don't forget 76/80. That's only about 1000 feet (0.19 miles).

[froggie]

That may be a roadgeek thing, but it may not even officially count, depending on if ODOT (and/or FHWA) measure by roadway centerline.  They could officially consider the two routes touching, but not duplexing, based on where the turnpike bridges over the freeway.

[Hot Rod Hootenanny]

That may be a roadgeek thing, but it may not even officially count, depending on if ODOT (and/or FHWA) measure by roadway centerline.  They could officially consider the two routes touching, but not duplexing, based on where the turnpike bridges over the freeway.

Otherwise one would have to include the I-74/80 bump over by the Quad cities as well.

[Duke87]

Otherwise one would have to include the I-74/80 bump over by the Quad cities as well.

Nope. Nowhere in that interchange to the two highways actually share pavement.

Look:

[Alps]

CR 569 and US 202 (NJ) - barely 100 ft on 569 SB/202 NB, about twice that in the other direction.

[mightyace]

Here is a jog of TN SSR 247 in Spring Hill:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Spring+Hill,+TN&sll=37.0625,-95.677068&sspn=47.569986,53.173828&ie=UTF8&hq=&hnear=Spring+Hill,+Maury,+Tennessee&ll=35.752701,-86.927972&spn=0.001543,0.003484&t=h&z=19&layer=t

It is roughly 100 ft.  To measure properly, use the satellite view as the map is a bit off and makes it longer.

It is signaled, basically, as one intersection and the duplex is unsigned.  Actually, it can be hard to know that 247 continues on both sides of 31.