SoylentNews is people
SoylentNews
Drivers are only too familiar with phantom traffic jams: those occasions when you slow to a complete standstill, which frustratingly appear to have no concrete cause. In fact, they do have a cause – just not an obvious one. Thanks to decades of scientific research, we now have theories that not only explain why jams happen but point to ways of preventing them.
Experiments on traffic flow date back to 1933 – just 25 years after Ford's Model T went on sale. American traffic engineer Bruce Greenshields took a movie camera out to a section of highway to record how many cars passed along it, and how long it took them.
...
For traffic, it was mathematicians James Lighthill and Gerald Whitham who came up with a theory to predict the properties of a highway. Inspired by "theories of the flow about supersonic projectiles and of flood movement in rivers", it used the physics of kinematic waves, treating traffic like particles in a liquid.The theory introduced the idea of shock waves in traffic. In places where cars slow up or accelerate, a traffic wave ripples back down the road. Waves, they said, were "likely to occur on any stretch of road where the traffic is denser in front and less dense behind."
...
In other words, traffic jams needn't be caused by a broken down vehicle or an accident. Just as, under the right conditions, a speck of dust can cause water vapor to condense into liquid in a cloud, the actions of a single driver could cause a jam.MIT traffic researcher Prof Berthold Horn explains: "Suppose that you introduce a perturbation by just braking really hard for a moment, then that will propagate upstream and increase in amplitude as it goes away from you. It's kind of a chaotic system. It has positive feedback, and some little perturbation can get it going."
Horn has developed an algorithm that could smooth out traffic jams, technology permitting. If cars could sense the distance to other cars both ahead and behind them, they could keep an even distance between the two. A simulation shows the algorithm taking effect after the traffic first bunches up:
Interesting article worth reading in full, complete with illustrative animations.
(Score: 1) by elixir on Thursday January 21 2016, @06:34PM
I will never understand why situations such as this needs scientific research. I feel it is common sense for one to know how traffic occurs. I would argue that the most contributing factor of traffic on freeways and highways are people changing lanes and cutting off people who are driving faster. If you drive in traffic, you will realize that the lane moving slowest will cause drivers in that lane to want to change to the faster lanes as quick in possible, which causes more traffic.
The cause of traffic is the impatience of humans. Until you solve that, there will always be traffic.
(Score: 1) by YeaWhatevs on Thursday January 21 2016, @07:17PM
> Until you solve that, there will always be traffic.
Yes, I believe the whole point of this is to lay the groundwork for the self driving car.
(Score: 1) by elixir on Thursday January 21 2016, @07:28PM
I do not think it is wise to come up with an alternative solution that does not hit the root of the issue's cause. Self-driving cars will make humans even more impatient, which is the opposite of what we want. I believe a better solution would be education, so that we can teach people some morals.
(Score: 0) by Anonymous Coward on Thursday January 21 2016, @10:20PM
That wasn't a recommendation, it was pointing out that the study is probably meant to do so.
(Score: 0) by Anonymous Coward on Thursday January 21 2016, @11:13PM
People are more patient when they are occupied with something else. If someone in a self-driving car is reading/watching something then they probably will not care about traffic that much.
(Score: 5, Informative) by DeathMonkey on Thursday January 21 2016, @07:30PM
I will never understand why situations such as this needs scientific research. I feel it is common sense for one to know how traffic occurs.
Common sense is frequently wrong, that's why.
(Score: 1) by elixir on Thursday January 21 2016, @08:14PM
I respectfully disagree. If people had more common sense, there would be far less issues in the world. This would lead more time for useful scientific research, rather than trying to bypass the root of a problem.
(Score: 1, Insightful) by Anonymous Coward on Thursday January 21 2016, @09:20PM
Many many things are counter-intuitive, which is why common sense is often wrong. Almost anything to do with probability/statistics. People are horrible at judging area, so more often than not "common sense" leads them astray there too.
I attended some nonlinear dynamics seminars back in the late 80's having to do with traffic analysis. Common sense will tell you that, when someone steps on the brake, that propagates a wave back through traffic. However, you can have scenarios where traffic waves are propagating forwards as well. That's not common sense. in fact, an awful lot of wave dynamics is not common sense, which is why there is much ballyhoo every decade when an experiment shows that light exited a region before it entered it, or other "super-luminal" result, which is all caused because people don't have a common sense feel for the difference between phase and group velocities.
Our technical knowledge and scientific progress would be greatly stunted if we selected our topics of study based upon whether we feel we know something to be true.
(Score: 3, Funny) by tangomargarine on Friday January 22 2016, @02:52PM
Traffic patterns that violate causality/relativity?
Man I want to subscribe to *your* newsletter.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 0) by Anonymous Coward on Friday January 22 2016, @04:55PM
Well, you basically make my point. The forward propagation waves have to do with the difference between group and phase velocity.
I don't have a newsletter, but you are welcome to start with the "waves" section of any Physics 101 book.
(Score: 0) by Anonymous Coward on Thursday January 21 2016, @10:55PM
I respectfully disagree. If people had any sense at all, there would be far less issues in the world.
There. FTFY.
(Score: 1, Insightful) by Anonymous Coward on Thursday January 21 2016, @07:58PM
Actually, the cause of traffic problems is too many cars on the road.
(Score: 3, Informative) by davester666 on Friday January 22 2016, @04:38AM
There's also merging. There seem to be three types of people
1. People who get up to the same speed as traffic, position their vehicle between two vehicles and merge.
2. People who have to get ahead as much as they, go faster than traffic, even passing other cars that are trying to merge, get to the end of the merging area, slam on the brakes and cut off whoever happens to be there. If traffic is at a standstill, surrounding drivers should get out and beat the crap out of him. Then roll his car into the ditch. With him in the trunk.
3. People who don't get up to speed, seem to be more unsure of their driving skills, are unable to merge on their own and get to the end of the merging area and come to a stop. Requires that traffic on the highway come to a complete stop, at least in the merging lane, in order for them to continue. Probably should have their drivers license taken away.