Shockwave Traffic Jams Recreated for the First Time

[fredr123]

Because we haven't argued about traffic and driving habits for a while now...


Scientists in Japan have recreated the shockwave traffic jam in a laboratory setting (link has video). According to the story:

Traffic that grinds to a halt and then restarts for no apparent reason is one of the biggest causes of frustration for drivers. Now a team of Japanese researchers has recreated the phenomenon on a test-track for the first time.


The mathematical theory behind these so-called "shockwave" jams was developed more than 15 years ago using models that show jams appear from nowhere on roads carrying their maximum capacity of free-flowing traffic – typically triggered by a single driver slowing down.

[Regulator75]

I was hoping this story included this guy causing some Japanese rampage...

[icarus]

Traffic jams are caused by one or more people going slow? This is groundbreaking stuff.

[Ozy_Flame]

I knew it! There is absolutely no reason for traffic jams to get start and stop again, its just bad drivers who can't change lanes and are too passive to do anything. Multiply this by about 50 cars doing this, and you've got 50 people or so who are holding up a good 500-1000 cars on a stretch of highway.

If I didn't take the bus, I think I'd go beserk.

[LeftWing]

its just bad drivers who can't change lanes

I think that choke points (dropping four lanes to three, etc.) and merge points add to this problem significantly. The phenomenon aggravates me as well (every day), but I would blame the majority of this on poor infrastructure than bad drivers.

Even the best drivers in the world are going to have to slow down to exit Deerfoot onto Memorial or merge onto Deerfoot North from 17th during rush hour. The roads simply don't have the capacity to deal with the numbers.

[Bill Bumface]

^ What they're talking about in the article is when a road is operating near or past capacity, and on person slows down for any reason, the person behind them slows even more to make up for the time it took them to react, and it travels back eventually stopping traffic. If you have a road that does not drop any lanes (Crowchild headed away from downtown for instance) you can see this happen every once in a while when someone does something stupid. The more cars on the road, the shorter the following distances, the more this is exagerated. Someone posted up a really cool online model of this once, but I'm not sure where it is.

[Nufy]

Try I-95 in Connecticut at 7:00 am.

Happens every 10 miles or so.

Very frustrating..........

[Bill Bumface]

Originally Posted by fotze

I've wondered if you magically translplanted Manhattan drivers onto Calgary streets and Calgary driver into Manhattan. My theory is that Calgary's traffic "problems" would decrease by a significant amount and Manhattan would be an absolute disaster.

It blows me away how many people lollygag at a red light turning green. Take Memorial at 10th stret at rush hour. There is ALWAYS at least one person that follows 18 car lengths behind the previous guy meaning that 10 cars fail to make it throught the light. I just hope someday driving slower than the speed limit and being inattentive is recognized as the hazard that it is, not to mention the amount of greenhouse gas emissions it creates.

When you prevent 10 cars from getting through a light you have cost those 10 people to lose 2 minutes of their life, but you are also affecting 10 people behind them and it just keeps going. That's 20 minutes per light change you have caused to people behind you. So if you look at it the right way you have kept people against their will, in essence, kidnapping them. I know I am being a bit ridiculous, but maybe people will look at not paying attention at a light as being much more selfish than previously believed.

I agree. One thing that will prevent us from ever being like Manhattan is that we have redlight cameras, where as in Manhattan I saw several people run reds right in front of cops without the cop caring at all. People are so paranoid here at intersections, especially since red light cameras. If someone uses their ABS to stop on dry pavement in front of me at Crowchild and 24th one more time...

[fredr123]

Originally Posted by hulkrogan

^ What they're talking about in the article is when a road is operating near or past capacity, and on person slows down for any reason, the person behind them slows even more to make up for the time it took them to react, and it travels back eventually stopping traffic. If you have a road that does not drop any lanes (Crowchild headed away from downtown for instance) you can see this happen every once in a while when someone does something stupid. The more cars on the road, the shorter the following distances, the more this is exagerated. Someone posted up a really cool online model of this once, but I'm not sure where it is.

BlackArcher101: http://forum.calgarypuck.com/showthr...487#post989487

[J pold]

The worst is the southland merger

Living in the south I can’t count the amount of times I have seen morons not know how to merge and cause huge traffic back ups

Granted whoever design it deserves a punch in the face, you constantly have people needing to get over 2 lanes of traffic and only 500m or so to do it

And of course there is that one person who doesn’t realize it until they have about 10m left and cut across 3 lanes of traffic almost always casing an accident

[calculoso]

Originally Posted by fotze

It blows me away how many people lollygag at a red light turning green. Take Memorial at 10th stret at rush hour. There is ALWAYS at least one person that follows 18 car lengths behind the previous guy meaning that 10 cars fail to make it throught the light. I just hope someday driving slower than the speed limit and being inattentive is recognized as the hazard that it is, not to mention the amount of greenhouse gas emissions it creates.

When you prevent 10 cars from getting through a light you have cost those 10 people to lose 2 minutes of their life, but you are also affecting 10 people behind them and it just keeps going. That's 20 minutes per light change you have caused to people behind you. So if you look at it the right way you have kept people against their will, in essence, kidnapping them. I know I am being a bit ridiculous, but maybe people will look at not paying attention at a light as being much more selfish than previously believed.

But but but... It's the people that speed that are the problem!!!!

[arsenal]

We need to implement european traffic lights.
At least in germany they go:
Green -> Yellow -> Red -> Yellow -> Green.

So if you aren't moving by the time the light is green, you get honked at. Plus no one runs a yellow light because they know if they do, they will probably cause an accident.

[jayswin]

Originally Posted by calculoso

But but but... It's the people that speed that are the problem!!!!

No kidding eh? I hate people that think speeding is the be all and end all of traffic problems, and that driver inexperience, slow drivers, lolligagers etc, aren't problems at all.

[worth]

There is a driver on 88th/84th street SE going north after 22x every morning at about 6:30am that drives about 20km under the speed limit which creates a pileup of traffic behind the driver which makes people pass in the oncoming lane crossing over a solid yellow line. I swear someone is going to get killed trying to pass this dufus. People going under the speed limit etc are just as dangerous as people speeding.

[rockstar]

Why do the speeders have to turn this into another debate between fast drivers and slow drivers and who's more dangerous?!!?

[ken0042]

Agreed Rockstar. Let's keep this on topic; not every driving thread has to be a debate about speeding.

In case anybody isn't clear; the subject is the cause of traffic jams.

[Bobblehead]

Originally Posted by ken0042

Agreed Rockstar. Let's keep this on topic; not every driving thread has to be a debate about speeding.

In case anybody isn't clear; the subject is the cause of traffic jams.

But it is always <insert favourite scapegoat here>'s fault. I don't know why people even argue. You must agree with Hitler if you think otherwise!



Back on topic, I recall reading a couple years ago that if 15% of vehicles had the equipment that would automatically maintain the correct distance in front of them then it would smooth out all these "shockwave" situations. Since these systems can read the closing rate and minimize the amount of braking that they aren't prone to the cascading effect.

[Dan02]

Originally Posted by fotze

I've wondered if you magically translplanted Manhattan drivers onto Calgary streets and Calgary driver into Manhattan. My theory is that Calgary's traffic "problems" would decrease by a significant amount and Manhattan would be an absolute disaster.

I absolutely agree, just got back from a trip to LA and let me tell you if half the drivers here went down there they'd get their ass run off the road. if you can't merge they don't let you in. How so many people in this city can't understand a merge is simply stunning. It's a good thing that parallel parking is the be all and end all of the driving test!

some days i wish my truck came equiped with a RPG. Check that. pretty much every day.