Nice. I had a quick look at this effect in an old blog post, it's surprisingly simple to derive the existence of waves in traffic flow (given some simplifying assumptions)
http://jasmcole.com/2014/09/14/only-a-fool/
What Are Traffic Waves and Why Do They Happen So Much?
21–30 of 97 posts
Re: What Are Traffic Waves and Why Do They Happen So Much?
#22Earlier quoted context omitted.
Is it based on your own experience? Or you read it somewhere? In which countries did it happen more?
The last time I counted, I have driven in 12 different countries. I found this certainly happens a lot in South Africa and a bit in various parts of Spain and Ireland. It seems to happen a lot less in the UK and Portugal.
Funny you say that about Portugal. I'm Portuguese, and I concur, although I always thought of my opinion as biased.
It does not take many drivers acting responsibly to fix a wave jam. Interestingly, culturally, is that this responsible action is viewed here as a relaxed take on traffic. When the line restarts, some drivers take their time shifting into first gear, and then take a lot of time to increase their speed. They effectively buffer cars behind them from the stop-and-go.
If you get two of these in a row, it's enough for the stop and go effect to dissipate.
If you do this on the road, prepare to be overtaken by someone "in a rush", and prepare to ignore the action, although it's acceptable to gesticulate and swear at the car ahead :-)
Re: What Are Traffic Waves and Why Do They Happen So Much?
#23I find this happens a lot more in some countries than others, and it's not down to levels of traffic on the road, it's down to driving habits. I think the UK has done well with driver education and variable speed limits to mitigate this, and zipper merging is the norm.
I think has a lot to do with manual transmission which allows for natural and controlled engine breaking, thus not creating the brake light to come on (and therefore the wave of copy-cat type braking).
Re: What Are Traffic Waves and Why Do They Happen So Much?
#24I find this happens a lot more in some countries than others, and it's not down to levels of traffic on the road, it's down to driving habits. I think the UK has done well with driver education and variable speed limits to mitigate this, and zipper merging is the norm.
I think has a lot to do with manual transmission which allows for natural and controlled engine breaking, thus not creating the brake light to come on (and therefore the wave of copy-cat type braking).
The worst I've seen has been in Johannesburg in South Africa, where automatic transmission is rare. I used to refer to it as concertina traffic before I knew it was called a traffic wave, and the concertina is a popular instrument in South Africa amongst the ancestors of the people who are usually responsible for these waves.
Re: What Are Traffic Waves and Why Do They Happen So Much?
#25Earlier quoted context omitted.
I think people overstate the degree to which self-driving cars will actively 'talk' to each other. And I actually think it's somewhat detrimental to advocating for self-driving cars, because the immediate thought is that communication acting as a channel for malware. And that's a fairly justified fear. In the end, I think most of the communication will just be in terms of the fact that self-driving cars interacting w…
I expect in the short run we'll see different tribes of self-driving cars - say Google vs. Uber - who will actively communicate cooperatively with their in-group, but actually compete against the out-group, depending upon whether or not their host companies decide to cooperate or not. In the long run, I expect cars to become smart enough to be self-owning, in which case it's every car for himself.
We can see today that the automotive industry is receptive to regulation, even at the expense of competitive edge, when the thing being optimized for is in the name of safety. I imagine that even if there is a pattern of the sort you describe, it will be limited to the adolescence of the whole thing.
If we get sufficiently far out (decades in, after human-driven cars are completely gone, not just out of obsolescence, but due to being outlawed at least for certain areas), I'd bet that what we'd see are demands for compliance that resemble the restrictions on automakers that we have now. I imagine that the driving programs would eventually be in the hands of some regulatory agency, with municipalities being allowed some control of the parameters.
Re: What Are Traffic Waves and Why Do They Happen So Much?
#26This reminds me of a piece on traffic I read quite a few years ago and might have been on reddit or even perhaps slashdot. I still follow its advice to this day when having to brave the 101. It discussed traffic waves and our reactions to them. The repeatable waves this article mentions come from (most of) the individual drivers driving faster than the capacity of the road to carry them all. So they bunch up at some…
One problem of the "car idle" in terms of humans is that it takes almost constant attention to make sure you don't bump into the cars in front. Compare that to the speed-up/break/slow-down which allows time to relax. In my own driving I tend to have a more relaxed speed-up/slow-down cycle which is somewhere in-between the two modes you describe.
Not to mention that, in the country I live in, it is guaranteed that while you're idly rolling forward, some asshole will cut you off and take your place so that he can win that precious 2 seconds.
Re: What Are Traffic Waves and Why Do They Happen So Much?
#27I'm pretty convinced that self driving cars can fix this. Reaction times will be much faster and they can network together to spread out the braking and acceleration. Possibly even merging at high speed.
Re: What Are Traffic Waves and Why Do They Happen So Much?
#28I'm pretty convinced that self driving cars can fix this. Reaction times will be much faster and they can network together to spread out the braking and acceleration. Possibly even merging at high speed.
A more powerful potential mechanism is that they can be programmed to respect do not enter directives from a traffic control system (keeping human drivers off a freeway would take a lot of infrastructure). So the amount of traffic on the road can be regulated to keep it below the capacity implied by the safe response time of the vehicles.
Re: What Are Traffic Waves and Why Do They Happen So Much?
#29Earlier quoted context omitted.
I think people overstate the degree to which self-driving cars will actively 'talk' to each other. And I actually think it's somewhat detrimental to advocating for self-driving cars, because the immediate thought is that communication acting as a channel for malware. And that's a fairly justified fear. In the end, I think most of the communication will just be in terms of the fact that self-driving cars interacting w…
And that's assuming error free communications, near latency free communications and non-congestion as well as perfect hardware. Is 'no signal' the same as 'no other cars' or 'broken radio(s)'? Self driving cars have all the elements of a distributed computing system only now it's moving at a pretty good clip and lives are at stake. 'Move fast and break something' is very bad advice and 99.999% uptime is not going to…
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Re: What Are Traffic Waves and Why Do They Happen So Much?
#30Earlier quoted context omitted.
I expect in the short run we'll see different tribes of self-driving cars - say Google vs. Uber - who will actively communicate cooperatively with their in-group, but actually compete against the out-group, depending upon whether or not their host companies decide to cooperate or not. In the long run, I expect cars to become smart enough to be self-owning, in which case it's every car for himself.
We can see today that the automotive industry is receptive to regulation, even at the expense of competitive edge, when the thing being optimized for is in the name of safety. I imagine that even if there is a pattern of the sort you describe, it will be limited to the adolescence of the whole thing. If we get sufficiently far out (decades in, after human-driven cars are completely gone, not just out of obsolescence,…
You're probably right, this is a far more realistic scenario. I have a bit of a soft spot for dystopia.