Projects that Moved the Traffic Problem Downstream

[webny99]

Many of today's major construction projects are designed to alleviate bottlenecks, improve geometry, and/or add capacity to the road network. In most cases, such spot improvements achieve said objective, improve traffic flow, time passes, and little thought is given to the impact on other areas of the corridor(s).

In contrast, there are some cases where a project helps traffic flow in one area, thereby moving the constraint downstream, to another area which actually had minimal congestion until the project down the road improved flow into the area! The recent NY 531 Terminus Improvement Project in the town of Ogden, NY, is a classic example. Previously, Brockport-bound (westbound) traffic had to make a right turn at the end of NY 531, followed by an immediate left turn onto NY 31. The second stoplight only permitted so many vehicles to turn left per cycle, meaning there was never an overload onto NY 31. In fact, those two consecutive turns were the bottleneck, with traffic backing well onto the freeway portion of NY 531. Now, westbound traffic can proceed straight through the NY 531/NY 36 intersection, i.e. NY 31 was re-aligned so the dominant traffic flow doesn't have to make any turns. The traffic signal at NY 531/NY 36 is padded with a lot of green space for east-west traffic, so as much traffic as NY 531 can handle, can flow through the intersection and onto NY 31. All of a sudden, all this traffic that was previously released in small batches, is now continually flowing onto NY 31. Which is bad news for the NY 31/NY 260 intersection (located two miles downstream), which can no longer handle the volumes, and has become the new bottleneck, with back-ups of up to a mile every weekday afternoon.

(Yes, NY 531 most definitely should have been continued as a freeway all the way to Brockport, and I would not be here composing this post, but that is another matter altogether...)

Any other examples of a construction project alleviating one problem only to cause another one, just as bad, down the road?

[silverback1065]

I made a thread about this a while back. In Indianapolis, they turned us 31 into an interstate, they fucked up the lane configuration, and didn't expand 465 where the highway ends, now it backs up at that interchange every day.

[US 89]

The best example I can think of would be I-15 in Utah County. Before any reconstruction of I-15 happened, the whole thing was 3 lanes in each direction plus one HOT lane, which was undeniably inadequate. Eventually, the part south of SR-73 was reconstructed and widened in the I-15 CORE project, and a few years later the same was done north of SR-92 in the Point Project. That left a 3+1 bottleneck between SR-73 and SR-92, with 4+1 or 5+1 configurations on either side. This is finally being fixed as part of the I-15 Tech Corridor project, which should be done in a couple years.

[inkyatari]

Does the Hillside Strangler count here?

[Brandon]

Does the Hillside Strangler count here?

I'd say it's the quintessential project for this thread.  IDOT moves the merge point east of Mannheim, traffic issue is the same as before.

[bzakharin]

NJ Turnpike's multiple extensions of the Car / Truck lane setup southward come to min. Of course it's not quite moving the problem downstream as much as the problem reappearing downstream some time afterward as traffic volumes increase.

[Mergingtraffic]

In CT, the widened I-95 south between Exits 15-14 with a long aux lane.  The choke point used to be at the Exit 15 on-ramp.  NOW, the choke point is down at the Exit 13 on-ramp because traffic is flowing at exits 15-14. There are NO plans on fixing Exit 13, so we are stuck with it for now.

[shadyjay]

Also in CT, in 1993 when the Baldwin Bridge was replaced with an 8-lane structure, I-95 on either side failed to be widened, so you still have essentially 2 thru lanes in each direction with the rest being operational lanes.  Granted, it gives traffic entering I-95 NB more time to merge, but as soon as you're touched down on the east bank, you have 1/4 mile before the 3rd lane ends and you're right back to two lanes. 

Widening as part of an early phase of the "Q" Bridge project took care of I-95 out to Exit 54 in Branford.  But once you're 3/4 mile or so from that interchange, the backup starts.  So it just got pushed a few miles further east of where the 3-lane section used to end at Exit 51/East Haven.

[Bruce]

Almost all of them, thanks to the wave of development that crops up with the new road.

[1995hoo]

I'm positive we had this discussion a while back, although obviously it's always something that can be updated.

Edited to add: https://www.aaroads.com/forum/index.php?topic=21680.0

[jeffandnicole]

Almost all of them, thanks to the wave of development that crops up with the new road.

Which started with train commuting, which made moving out of cities possible in the 1800's.

[Brandon]

Almost all of them, thanks to the wave of development that crops up with the new road.

Which started with train commuting, which made moving out of cities possible in the 1800's.

And, as an example:
Riverside, Illinois.  Specifically designed as a bedroom community in 1869, connected to the Loop via train.

[kphoger]

Almost all of them, thanks to the wave of development that crops up with the new road.

Which started with train commuting, which made moving out of cities possible in the 1800's.

And, as an example:
Riverside, Illinois.  Specifically designed as a bedroom community in 1869, connected to the Loop via train.

And Frank Lloyd Wright moved to Oak Park in order to get out of the city.

[RobbieL2415]

Traffic isnt my primary concern with highway design. Safety and flow characteristics are.  A well designed interchange that allows for straighforward movements can still back up during rush hour but if the flow of traffic is steady then I'd consider it a win.  Short off ramps, weaving interchanges, substandard interchanges and thoughtless design make the traffic more stop and go.  That's why I don't think adding a lane to the Merritt/W. Cross Parkways will make the daily congestion lighter.  You'd still have a winding carriageway and abrupt ingresses and egresses to deal with and more than ever those are what slow downs motorists. Traffic backs up before a hill, then flies down the other side. Bottleneck before a sharp bend left, relieved soon after. Rinse and repeat.

[ET21]

Does the Hillside Strangler count here?

I'd say it's the quintessential project for this thread.  IDOT moves the merge point east of Mannheim, traffic issue is the same as before.

Runner up will be the Kennedy from Harlem eastward inbound once they finish the extra lane expansion

[DJ Particle]

US-169 at I-494 in Eden Prairie, MN

Until a few years ago, it was a signalized intersection for US-169, and rush hour traffic would always choke on southbound 169 at the lights (3 in a row..one for each direction of 494, and a light just barely south of that for 78th St)

Now, it's a freeway-to-freeway interchange, with a flyover going from 494 West to 169 South (and stumps suggest another flyover from 494 East to 169 North is in the future).  The flyover traffic merges into 169 South...then ramp traffic from 494 East merges in...now each has their own utility lane, but then the lane from 494 E ends, then the lane from 494 W eventually feeds right into Exit 119.

So you have 4 lanes merging into 2... in the span of about 3/4-mile.

The gridlock didn't disappear.  It's just a slight bit further south.

[paulthemapguy]

Does the Hillside Strangler count here?

I'd say it's the quintessential project for this thread.  IDOT moves the merge point east of Mannheim, traffic issue is the same as before.

This is the first thing that came to mind.  I-15 at SR-92 was the second, and that was also covered upthread.  So good job guys lol

Moving the traffic jam on I-290 farther east might have been advantageous just because it took some of the jamming out of the interchange with I-294/88.  People going from EB I-88 to NB I-294, for example, may have to suffer less as a result.  You knew IDOT/ISTHA knew they were just relocating the traffic jam.  But maybe doing that could be a helpful thing for people other than those going from I-88 EB to I-290 EB.

[inkyatari]

Does the Hillside Strangler count here?

I'd say it's the quintessential project for this thread.  IDOT moves the merge point east of Mannheim, traffic issue is the same as before.

This is the first thing that came to mind.  I-15 at SR-92 was the second, and that was also covered upthread.  So good job guys lol

Moving the traffic jam on I-290 farther east might have been advantageous just because it took some of the jamming out of the interchange with I-294/88.  People going from EB I-88 to NB I-294, for example, may have to suffer less as a result.  You knew IDOT/ISTHA knew they were just relocating the traffic jam.  But maybe doing that could be a helpful thing for people other than those going from I-88 EB to I-290 EB.

IMHO, I think getting rid of the side by side 294 / 290 for the two or so miles is key to solving this problem.

[Brandon]

Does the Hillside Strangler count here?

I'd say it's the quintessential project for this thread.  IDOT moves the merge point east of Mannheim, traffic issue is the same as before.

This is the first thing that came to mind.  I-15 at SR-92 was the second, and that was also covered upthread.  So good job guys lol

Moving the traffic jam on I-290 farther east might have been advantageous just because it took some of the jamming out of the interchange with I-294/88.  People going from EB I-88 to NB I-294, for example, may have to suffer less as a result.  You knew IDOT/ISTHA knew they were just relocating the traffic jam.  But maybe doing that could be a helpful thing for people other than those going from I-88 EB to I-290 EB.

IMHO, I think getting rid of the side by side 294 / 290 for the two or so miles is key to solving this problem.

Actually, that might make it worse.  Instead of keeping the two traffic streams separate as they are now (and are at I-88 and I-355), you would introduce a massive amount of merging.  And with the way the locals love to lane jockey, it would be a nightmare.

Don't cross the streams.

[ET21]

Does the Hillside Strangler count here?

I'd say it's the quintessential project for this thread.  IDOT moves the merge point east of Mannheim, traffic issue is the same as before.

This is the first thing that came to mind.  I-15 at SR-92 was the second, and that was also covered upthread.  So good job guys lol

Moving the traffic jam on I-290 farther east might have been advantageous just because it took some of the jamming out of the interchange with I-294/88.  People going from EB I-88 to NB I-294, for example, may have to suffer less as a result.  You knew IDOT/ISTHA knew they were just relocating the traffic jam.  But maybe doing that could be a helpful thing for people other than those going from I-88 EB to I-290 EB.

IMHO, I think getting rid of the side by side 294 / 290 for the two or so miles is key to solving this problem.

Actually, that might make it worse.  Instead of keeping the two traffic streams separate as they are now (and are at I-88 and I-355), you would introduce a massive amount of merging.  And with the way the locals love to lane jockey, it would be a nightmare.

Don't cross the streams.

Never... EVER.... cross those streams. It's bad enough as is, but if these merges occurred that section would be gridlock 12 hours a day

[froggie]

^ Not necessarily.  There's definitely a very slim chance we'll survive...

[Joe The Dragon]

Does the Hillside Strangler count here?

I'd say it's the quintessential project for this thread.  IDOT moves the merge point east of Mannheim, traffic issue is the same as before.

This is the first thing that came to mind.  I-15 at SR-92 was the second, and that was also covered upthread.  So good job guys lol

Moving the traffic jam on I-290 farther east might have been advantageous just because it took some of the jamming out of the interchange with I-294/88.  People going from EB I-88 to NB I-294, for example, may have to suffer less as a result.  You knew IDOT/ISTHA knew they were just relocating the traffic jam.  But maybe doing that could be a helpful thing for people other than those going from I-88 EB to I-290 EB.

IMHO, I think getting rid of the side by side 294 / 290 for the two or so miles is key to solving this problem.

IL-tollway is paying the big $$$ to fix it.
https://www.illinoistollway.com/outreach/projects-in-your-community/central-tri-state-tollway-i-294/290-88-interchange-project

[Gnutella]

PA 28 in Pittsburgh. The segment between I-279 and Millvale used to be a dangerous four-lane undivided highway with signalized intersections at the 31st and 40th Street Bridges. When it wasn't slammed with traffic, it had an extremely high crash and fatality rate. To illustrate what a failure of civil engineering it was, traffic flow improved during the reconstruction. Now that it's been reconstructed halfway to Interstate standards, the bottleneck that used to exist there has now moved north to the Highland Park Bridge, where the highway briefly drops a lane at the off-ramps and adds it back at the on-ramps. The good news is, PennDOT has already designed the upgraded interchange, which will be reconstructed very soon.

[TheHighwayMan3561]

US-169 at I-494 in Eden Prairie, MN

Until a few years ago, it was a signalized intersection for US-169, and rush hour traffic would always choke on southbound 169 at the lights (3 in a row..one for each direction of 494, and a light just barely south of that for 78th St)

Now, it's a freeway-to-freeway interchange, with a flyover going from 494 West to 169 South (and stumps suggest another flyover from 494 East to 169 North is in the future).  The flyover traffic merges into 169 South...then ramp traffic from 494 East merges in...now each has their own utility lane, but then the lane from 494 E ends, then the lane from 494 W eventually feeds right into Exit 119.

So you have 4 lanes merging into 2... in the span of about 3/4-mile.

The gridlock didn't disappear.  It's just a slight bit further south.

You also have the rebuilt Crosstown Commons where a massive part of the problem with the old interchange was the eastbound MN 62 lane drop at Lyndale. So what did they do instead of, you know, making it two thru lanes through the whole interchange?

Move the lane drop to Nicollet instead.

[froggie]

^ MnDOT was already breaking the bank as it was on the Crosstown project.  To properly address the issue would have required extending the project limit to Cedar, replacing the Portland bridge, filling in some wetlands on the north side of Legion Lake, addressing both the frontage roads and the Bloomington ramps, and all in all would have added several tens-of-millions of dollars to the price tag....easily $30 million, probably more.