How do junctions become "malfunction junctions"?

[cbalducc]

Every large city has at least one "Malfunction Junction".  How did they get that way?  God bless.

[agentsteel53]

despite the recent popularity of television and video games, people's favorite hobby remains reproduction. 

[ftballfan]

Here are the Malfunction Junctions in Michigan (in my humble opinion).
Detroit: All freeway interchanges east of Southfield and south of 8 Mile; also I-696/M-10/US-24; I-96/I-696/M-5; I-94/US-24 was one until it was SPUIfied a few years ago
Grand Rapids: I-96/US-131/M-37; I-196/US-131; I-96/I-196/M-37
Jackson: I-94/US-127/M-50 (the western interchange; mostly because the US-127 freeway gives up just north of here)
Lansing: I-496/US-127/Trowbridge Rd

[InterstateNG]

I-96/I-696/M-5

It may be complicated but it moves traffic well.

[RoadWarrior56]

Sometimes it is a poor design, but often it is just a bottleneck caused by too much traffic using it and a lack of alternate routes.  A classic case is I-85/I-285 NE of Atlanta. The current design is actually very good by itself, but can't handle the traffic demand, especially for the EB 285 to NB 85 movement.  A two-lane directional ramp is not enough, and would not be easy to fix.

[6a]

can't handle the traffic demand, especially for the EB 285 to NB 85 movement.  A two-lane directional ramp is not enough, and would not be easy to fix.

I think that's the classic example.  Traffic outstrips design, and the fix is horribly costly or complicated.  The easiest solution remaining is to leave it as-is.  Problems occur when there isn't at least a semi-viable alternative (like 85/285) so you're left with a malfunction junction.

[Brandon]

The new I-55/355 interchange (Exit 269) here is a malfunction junction outbound at rush hour.  The reason you ask since it is so new?  IDiOT in their infinite wisdom failed to add an auxiliary lane between there and IL-53 interchange (Exit 267) for the volume of traffic entering I-55 Sbd.  Likewise, the area is a malfunction Nbd in the morning for the same reason.  A lot of traffic entering at IL-53 with nowhere to go.  An auxiliary lane in each direction would solve the problem with a minimum of cost, IMHO.

[Mergingtraffic]

I would also add in NIMBYism and design.  A lot of interchanges are downgraded to suit the NIMBYs, ie a stack becomes a cloverleaf etc.  Sometimes other roads and alternative routes that were to supplement the interchange never get built.

[hobsini2]

The new I-55/355 interchange (Exit 269) here is a malfunction junction outbound at rush hour.  The reason you ask since it is so new?  IDiOT in their infinite wisdom failed to add an auxiliary lane between there and IL-53 interchange (Exit 267) for the volume of traffic entering I-55 Sbd.  Likewise, the area is a malfunction Nbd in the morning for the same reason.  A lot of traffic entering at IL-53 with nowhere to go.  An auxiliary lane in each direction would solve the problem with a minimum of cost, IMHO.

ABSOLUTELY!!! Hence why "they" are called IDiOT by so moany here.
And all they had to do was look at the east area of the interchange to Lemont Rd. Built the 4th lanes and other than the normal rush hour traffic northbound, it is wide open.

[Henry]

Sometimes it is a poor design, but often it is just a bottleneck caused by too much traffic using it and a lack of alternate routes.  A classic case is I-85/I-285 NE of Atlanta. The current design is actually very good by itself, but can't handle the traffic demand, especially for the EB 285 to NB 85 movement.  A two-lane directional ramp is not enough, and would not be easy to fix.

The old I-95/I-395/I-495 interchange south of DC is another classic example. To continue onto I-95 south, you had to exit to the right and then cross over I-495. It made sense when I-495 was the only interstate signed on the Beltway, but then it became nightmarish when they added I-95 to the mix.

[Alps]

In NJ, what happened is interchanges generally started off quite simply. Take US 9 at Smith Rd., for example. (And New Brunswick Ave., and NJ 184, which was former 440.) Three separate interchanges or even once intersections, all standard. Then add the Garden State Parkway, which originally ran to the outside of US 9 there. Then add the I-287/NJ 440 freeway. Some of the original roads remain in place, others are obliterated (half of the original 9/Smith interchange is intact, for example). Some of the original overpasses are reused for different roads, sometimes even switching direction (there's an original 1930s overpass at the I-95/NJ 4/US 9W/US 1-9-46 interchange that fits this description). So basically, all the complication comes from trying to reuse existing infrastructure as much as possible instead of just wiping the slate clean and starting over. (This is why US 46/NJ 23/I-80 is so messed up - it incorporates pieces of the original circle's overpasses and geometry here and there.) Many other states, such as Texas, would just construct a new interchange from scratch and reroute traffic around it during construction.

[Interstate Trav]

Every large city has at least one "Malfunction Junction".  How did they get that way?  God bless.

Is it pretty much always, just the traffic volume's increase before the junction can be upgraded?  I know of many in the Los Angeles area, I-10/I-605, US-101/I-405, I-10/I-405, I-10/I-5/US-101/SR-60.

[Bickendan]

The Ross Island Interchange (US 26/99W/OR 10/43) was pretty decent until I-5 and I-405 jumped on the bandwagon.