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MIT mathematicians model traffic jams like detonation waves

Most drivers have been stuck in a traffic jam at one point or another. Some of the jams are caused by an accident or closed lanes. Other traffic jams crop up with seemingly no reason.

A group of mathematicians at MIT is working on the development of a new model to explain how and why these so-call phantom traffic jams form. According to the researchers, these types of phantom traffic jams form when there are a lot of cars on the road and small disturbances like a driver hitting the brakes too hard or getting too close to another car. These little disturbances can escalate into a self-sustaining traffic jam.

The model developed by the team of researchers may help road designers build roads to minimize the possibility of phantom traffic jams. The key to the study is the discovery that the mathematics of these jams called jamitons are very similar to the equations used to describe the detonation waves produced by explosions.

The discovery of the jamitons allowed the researchers to solve traffic jam equations first theorized in the 1950's. The equations are reportedly similar to those used in fluid mechanics and model traffic jams as self-sustaining waves. The equations allowed the researchers to calculate the conditions that case a jamitons to form and how fast the jamiton will spread.

According to the researchers, once this type of jamiton forms it is nearly impossible to break up and a driver’s only choice is to wait the jamiton out. The researchers say that the new model can help road designers to determine speed limits that are safer and find stretches of road where accidents are more likely.

One of the researchers, Aslan Kasimov, said, "We wanted to describe this using a mathematical model similar to that of fluid flow." Kasimov and his team say that they discovered that jamitons have a sonic point that separates traffic flow into upstream and downstream components. Communication of the cause of the jamiton to drivers it the downstream segment of traffic is impossible say the researchers.



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RE: The source is pretty simple really
By omnicronx on 6/10/2009 12:02:36 PM , Rating: -1
Newsflash, if you are merging onto the highway you do not have the right of way! I always look far behind me to see when an opening is coming up and change my speed accordingly. Sure it would be nice if someone let you in, but they do not have to, it is your responsibility to merge safely not theirs.

Of course traffic jams are another situation, but when speeds are approaching 60+ MPH you have absolutely no excuse. There is always space to merge, you just may have to wait.


RE: The source is pretty simple really
By bhieb on 6/10/2009 12:16:25 PM , Rating: 2
quote:
Of course traffic jams are another situation, but when speeds are approaching 60+ MPH you have absolutely no excuse.


The whole point here is in jams or heavy traffic. And even at 60+ in heavy traffic the OP was saying it was the mergers fault. Assuming that there is no available "gap" then the bad driver here is not the guy trying to merge at speed, but the guy not following far enough back. A parking space worth of space at 60+ is too close. If a guy is coming on the ramp at speed and you refuse to let give him a 1/2 second release of the gas, then you are the one forcing the cut off. If he slams into you of course legally he was supposed to yield, but every class/book/teacher out there says you should make room if possible.


RE: The source is pretty simple really
By omnicronx on 6/10/09, Rating: 0
By omnicronx on 6/10/2009 12:48:47 PM , Rating: 1
And please do not bring 'How do I merge when there is a traffic Jam then, if nobody will let me in?' as this is beyond the scope of this study. It has nothing to do with traffic jams that have already occurred but the little things that occur before that could create or make traffic worse than it has to be down the line.


RE: The source is pretty simple really
By Xerstead on 6/10/2009 2:16:22 PM , Rating: 3
The right of way is held by those on the main highway. And if they are driving sensibly with at least a 2 second gap between them and the vehicle in front it is easy to merge with the trafic so the 'right of way' isn't really an issue. This also applies to people tailgating from the sliproad 'demanding' space for a group/stream of cars to join all at once. So back off and leave space.
The 3 car lengths mentioned above is nowhere near enough at those speeds.
quote:
I always look far behind me...

So you've built up enough speed on the sliproad to merge with the traffic, getting near enough the main carrageway to see the traffic... Ahhh, no space for 5,6,7+ cars back up the road. You now have 40 meters to hit your brakes AND STOP from over 60Mph. Hope the person behind you isn't doing the same and concentrating of the traffic 1/2 mile back up the main road as he ploughs into your rear. If you do survive that then you'll need to wait for an even biggher gap to get back up to speed.
quote:
it is your responsibility to merge safely not theirs.

But everybody has the responsibility to drive safely with consideration for other road users. Failure to leave enough space for merging traffic forcing them to hit the brakes is more likely to cause an accident.


By omnicronx on 6/10/2009 2:57:31 PM , Rating: 1
quote:
So you've built up enough speed on the sliproad to merge with the traffic, getting near enough the main carrageway to see the traffic... Ahhh, no space for 5,6,7+ cars back up the road. You now have 40 meters to hit your brakes AND STOP from over 60Mph. Hope the person behind you isn't doing the same and concentrating of the traffic 1/2 mile back up the main road as he ploughs into your rear. If you do survive that then you'll need to wait for an even biggher gap to get back up to speed.
I'm not too sure what you are trying to say here, you preach safe driving and you give a situation in which this is not the case. If there is a car in front of you on an on ramp, you are suppose to give space, a good 4-5 car lengths at least probably more so that you can accelerate and have time to compensate in case the flow of traffic changes. At this point what you are saying is a non issue, you can still find a space to merge and the person 4-5 car lengths behind you will also have ample time to merge.
quote:
But everybody has the responsibility to drive safely with consideration for other road users. Failure to leave enough space for merging traffic forcing them to hit the brakes is more likely to cause an accident.
If you read my posts, I agree with this. That being said if I am giving 3+ car lengths in front and behind me (not that I can control the cars behind), I am not going to slow down because someone can't figure out how to fit into the huge space in front and behind me.

The point here is you should not have to adhere to cars merging in the first place. If you leave enough space in front and behind you, and merging cars watch the oncoming traffic to find a spot to merge(following the advice above of course). This is far more ideal than anything you mention. Perhaps slowing down may be safe for you, but 1 mile down the road, cars also slowing down due to a snake effect that you just caused could be far more harmful in the long run. To others of course, and I guess is half the problem, what do you care as long as you are safe..


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