I 20 & I 59 run concurrent from Meridian, MS to Birmingham, AL for roughly 170 miles. Are there any others that run longer?
Definitely. Idk for certain, but I could safely say the I-80/I-90 concurrency in Ohio & Indiana may be the longest.
The 80/90 concurrency is about twice as long as 20/59.
As for longest concurrency involving an Interstate, I-25/US-87 takes the cake by a longshot. It's about 475 miles between Raton, NM, where 87 joins 25, and Glenrock, WY, where 87 leaves 25.
Quote from: pianocello on October 14, 2014, 12:39:26 AM
As for longest concurrency involving an Interstate, I-25/US-87 takes the cake by a longshot. It's about 475 miles between Raton, NM, where 87 joins 25, and Glenrock, WY, where 87 leaves 25.
I think they leave in Fountain, CO and part ways for several miles to return via ramps that do not exist.
Quote from: pianocello on October 14, 2014, 12:39:26 AM
As for longest concurrency involving an Interstate, I-25/US-87 takes the cake by a longshot. It's about 475 miles between Raton, NM, where 87 joins 25, and Glenrock, WY, where 87 leaves 25.
I-25/US 85 is longer, if we're including overlaps that the states ignore.
Oh, right. I forgot 85 made it all the way down to Texas.
The 40/85 concurrency in NC is not the longest, but it is a blast to drive. Not much in the way of speed traps and traffic tends to flow very fast there. Very well designed, IMO. :clap:
Quote from: Zzonkmiles on October 14, 2014, 01:52:16 PM
The 40/85 concurrency in NC is not the longest, but it is a blast to drive. Not much in the way of speed traps and traffic tends to flow very fast there. Very well designed, IMO. :clap:
A literal blast as well. I was once tailgated going 85 on that road.
Quote from: Thing 342 on October 14, 2014, 03:14:47 PM
A literal blast as well.
Why, did something explode? Or is that not a literal literal?
Quote from: Thing 342 on October 14, 2014, 03:14:47 PM
I was once tailgated going 85 on that road.
happens to me once every 3-400 miles on the freeway. nothing to write home about.
tailgated at 100 is something else - especially when you move over to let them by, and they move over because tailgating is fun shit.
Quote from: agentsteel53 on October 14, 2014, 04:26:58 PM
Quote from: Thing 342 on October 14, 2014, 03:14:47 PM
I was once tailgated going 85 on that road.
happens to me once every 3-400 miles on the freeway. nothing to write home about.
tailgated at 100 is something else - especially when you move over to let them by, and they move over because tailgating is fun shit.
I think they believe they're dogs who feel an extreme need to sniff up some one else's ass. Big, two-ton dogs.
Quote from: NE2 on October 14, 2014, 12:49:17 AM
Quote from: pianocello on October 14, 2014, 12:39:26 AM
As for longest concurrency involving an Interstate, I-25/US-87 takes the cake by a longshot. It's about 475 miles between Raton, NM, where 87 joins 25, and Glenrock, WY, where 87 leaves 25.
I-25/US 85 is longer, if we're including overlaps that the states ignore.
85 does leave the interstate in Fountain, so I don't know how that affects anything.
Quote from: roadman65 on October 14, 2014, 12:46:05 AM
Quote from: pianocello on October 14, 2014, 12:39:26 AM
As for longest concurrency involving an Interstate, I-25/US-87 takes the cake by a longshot. It's about 475 miles between Raton, NM, where 87 joins 25, and Glenrock, WY, where 87 leaves 25.
I think they leave in Fountain, CO and part ways for several miles to return via ramps that do not exist.
See above sentence.
Quote from: SD Mapman on October 15, 2014, 11:38:44 AM
Quote from: NE2 on October 14, 2014, 12:49:17 AM
Quote from: pianocello on October 14, 2014, 12:39:26 AM
As for longest concurrency involving an Interstate, I-25/US-87 takes the cake by a longshot. It's about 475 miles between Raton, NM, where 87 joins 25, and Glenrock, WY, where 87 leaves 25.
I-25/US 85 is longer, if we're including overlaps that the states ignore.
85 does leave the interstate in Fountain, so I don't know how that affects anything.
It's simple enough to calculate - Las Cruces to Fountain is longer than Raton to either Fountain or anywhere else. This does assume that US 85 never leaves the Interstates in New Mexico - the AASHTO log is unclear, probably because it was written before I-25 was complete.
I'm confused. Is your argument that US 85 leaves the interstate in Fountain but US 87 doesn't? Even so, the US 85 concurrency would still be longer, since it follows I-25 all the way to its end in Las Cruces. That's roughly 580 miles to Fountain, a full hundred more than pianocello's 475 figure for US 87.
ETA: Sorry, NE2 got here first, but yeah, what he said.
How are exit numbers handled on concurrent interstates?
Quote from: pctech on October 15, 2014, 01:26:40 PM
How are exit numbers handled on concurrent interstates?
there's always a route that's deemed "primary" whose exit numbers are used. I think it is usually the lowest-numbered of the set.
Quote from: pctech on October 15, 2014, 01:26:40 PM
How are exit numbers handled on concurrent interstates?
This is covered in the MUTCD: http://mutcd.fhwa.dot.gov/htm/2009/part2/part2e.htm#figure2E21
In short, either route can be used if both are Interstates. Usually it's the lower number or the one that was there first (e.g. I-40/85).
Quote from: agentsteel53 on October 15, 2014, 01:41:23 PM
Quote from: pctech on October 15, 2014, 01:26:40 PM
How are exit numbers handled on concurrent interstates?
there's always a route that's deemed "primary" whose exit numbers are used. I think it is usually the lowest-numbered of the set.
But not always, even if they were assigned at the same time.
I-90/94 in Illinois carries I-94's numbers even though both were assigned at the same time. I suspect this was due to I-90 not being complete between Schaumburg and Elmhurst (current I-290 after 1978).
I-80/294 uses I-294's mileposts (and exit numbers when assigned) as the road is also the Tri-State Tollway. I-74/280 uses I-74's mileposts.
Others:
I-55/72 and I-55/74 use I-55's mileposts and exit numbers (I-55 was the lower number).
I-57/64 and I-57/70 use I-57's mileposts and exit numbers (I-57 was the lower number).
I-55 and I-70 enter the state together (with I-64), yet I-70 continues I-270's mileposts and exit numbers after they separate (leading to a break in the space-time continuum of about 5 miles).
I-39/90 uses I-90's mileposts and exit numbers as I-90 was there first.
I-80/94 uses I-80's mileposts and exit numbers (I-80 was the lower number).
I-270 and I-280 continue their exit numbering from their previous states (Missouri and Iowa, respectively).
Quote from: Brandon on October 15, 2014, 02:20:10 PM
I-90/94 in Illinois carries I-94's numbers even though both were assigned at the same time. I suspect this was due to I-90 not being complete between Schaumburg and Elmhurst (current I-290 after 1978).
The 1975-76 official is the first with exit numbers, but shows no exit numbers at all on I-90, even on the Dan Ryan, despite I-94 north of Ohio-Ontario and south of the Skyway having numbers. The 1977-78 official shows I-90 exit numbers on the Ike, but only west of IL 50. The 1979-80 and 1981-82 officials show no exit number changes (I-290 continues to use I-90's mileage and no numbers on the JFK west of I-94). The 1983-84 official finally has the modern exit numbers, and is the first to put them on the Ike east of IL 50 and the Dan Ryan north of the Skyway. So in a sense, I-94 was there first, since using I-90's mileage would have either meant changing the numbers on the JFK or jumping from 51 to 97? at the Circle.
Quote from: Brandon on October 15, 2014, 02:20:10 PMI-55 and I-70 enter the state together (with I-64), yet I-70 continues I-270's mileposts and exit numbers after they separate (leading to a break in the space-time continuum of about 5 miles).
This is no longer the case, I-70 now enters IL separate from I-55 (and I-64, with which bumps).
Quote from: CNGL-Leudimin on October 15, 2014, 04:53:13 PM
Quote from: Brandon on October 15, 2014, 02:20:10 PMI-55 and I-70 enter the state together (with I-64), yet I-70 continues I-270's mileposts and exit numbers after they separate (leading to a break in the space-time continuum of about 5 miles).
This is no longer the case, I-70 now enters IL separate from I-55 (and I-64, with which bumps).
Oops, my bad (I should've known better - taken it two different times since it opened). It has about the same amount of mileage prior to meeting I-55, so the difference is negligible between the two.
I-75 has two concurrencies with lower-numbered interstates in Kentucky. In both cases, I-75's mileage and exit numbers are used.
What about three digit numbers overlapped with two digits? I have seen plenty that use the three digit route number exits such as around Knoxville, TN. I-75 uses I-640's exit numbering.
Then, as mentioned before, I-83 uses I-695's numbers even though no exits during the overlap, it is at the split that I-83 leaves I-695 with an exit number and not I-695 leaving I-83.
Quote from: roadman65 on October 16, 2014, 10:11:50 PM
What about three digit numbers overlapped with two digits? I have seen plenty that use the three digit route number exits such as around Knoxville, TN. I-75 uses I-640's exit numbering.
Then, as mentioned before, I-83 uses I-695's numbers even though no exits during the overlap, it is at the split that I-83 leaves I-695 with an exit number and not I-695 leaving I-83.
I-43 on I-894 uses the latter's exit #'s. My prediction is that US(I)-41 will do the same. I-39 uses US-51/former WIS-78 for the duration of the freeway in WI north of the Cascade Interchange with 90/94.
Quote from: roadman65 on October 16, 2014, 10:11:50 PM
What about three digit numbers overlapped with two digits? I have seen plenty that use the three digit route number exits such as around Knoxville, TN. I-75 uses I-640's exit numbering.
Then, as mentioned before, I-83 uses I-695's numbers even though no exits during the overlap, it is at the split that I-83 leaves I-695 with an exit number and not I-695 leaving I-83.
I-94/694 in the NW Twin Cities uses the 494/694 exit numbers. Theoretically there could be an exit number duplication along I-94 in Minnesota (30-34 range), but none of the exits in this short stretch duplicate any along I-94.
I-64 in Virginia gives up its own exit numbering where duplexed with both I-81 and I-95.
In both cases the other interstate with the higher number are the straight through routes, and in Richmond it was part of the tolled Richmond- Petersburg Turnpike where it always had its own sequential numbering from 1 to 17. Even in the past I-95 had to give up its own numbering until the toll road was allowed to use I-95's sequential system.
Quote from: Zzonkmiles on October 14, 2014, 01:52:16 PM
The 40/85 concurrency in NC is not the longest, but it is a blast to drive. Not much in the way of speed traps and traffic tends to flow very fast there. Very well designed, IMO. :clap:
I agreed completely. I drove on that stretch a lot and LOVED every minute of it. Everybody goes fast on that stretch. It sure feels like the stretch of I-95 between Richmond and Washington, D.C.
Quote from: Strider on October 17, 2014, 01:13:13 PM
Quote from: Zzonkmiles on October 14, 2014, 01:52:16 PM
The 40/85 concurrency in NC is not the longest, but it is a blast to drive. Not much in the way of speed traps and traffic tends to flow very fast there. Very well designed, IMO. :clap:
I agreed completely. I drove on that stretch a lot and LOVED every minute of it. Everybody goes fast on that stretch. It sure feels like the stretch of I-95 between Richmond and Washington, D.C.
Quote from: Strider on October 17, 2014, 01:13:13 PM
Quote from: Zzonkmiles on October 14, 2014, 01:52:16 PM
The 40/85 concurrency in NC is not the longest, but it is a blast to drive. Not much in the way of speed traps and traffic tends to flow very fast there. Very well designed, IMO. :clap:
I agreed completely. I drove on that stretch a lot and LOVED every minute of it. Everybody goes fast on that stretch. It sure feels like the stretch of I-95 between Richmond and Washington, D.C.
We must be long-lost twins. I LOVE the stretch of I-95 between Richmond and DC. I especially like how so much of the interstate there has the northbound and southbound lanes separated by the trees, so you are basically racing through the pines without the distraction of the oncoming traffic. Another fun section was I-85 in Virginia from Petersburg to the NC state line. It's not a concurrency, but it is still a fun and easy drive through the middle of nowhere.
I'll tell you which concurrency I DON'T like. It's that miserable I-75/85 garbage in Atlanta. Hell no!!!
Quote from: Zzonkmiles on October 22, 2014, 12:09:53 PM
I'll tell you which concurrency I DON'T like. It's that miserable I-75/85 garbage in Atlanta. Hell no!!!
I've always wanted to drive the Downtown Connector. I am sure traffic is a bitch through there, but if it's free flowing, it looks fun. I'd definitely drive it at an off peak time; either late at night or an early Sunday morning.
I love driving on the Atlanta connector when traffic is flowing... REALLY wide with lots of fun curves and underpasses go great with some loud fast music playing in the car.
During the weekday when traffic is a crawl, though, it's the worst drive ever.
BTW exit numbers follow I-75, I've always assumed because the I-75 mileage by that point is way higher than I-85 ever reaches in GA.
Thread resurrection!
I-73/I-74 in NC is multiplexing for 68 miles. (construction unfinished in some areas)
I-40/I-85 for 31 miles in NC
I-90/I-94 in IL and WI (they are the only interstates that met and concurrency twice)
I-20/I-59 in AL and MS
I-40/I-55; I-40/I-65, I-40/I-24, I-40/I-75 in TN
There are more out there.
As far as I know, I-80 and I-90 is the longest concurrence of all.
When I-69 gets done with construction between Martinsville and Indianapolis, I-69 will use I-465's exit numbers on the east side of Indy.
I-70 uses I-65's exit numbers from the South Split to the North Split in downtown Indianapolis.
I-74 uses I-465's mileage from the west side of Indy to the east side.
I-80 uses I-94's exit numbers until the Toll Road, then uses I-90's mileage from Lake Station to the Ohio state line.
The small overlap with I-87 and I-440 in Raleigh on its southern end to connect with I-40 utilizes I-440 exit numbers and mileage.