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Can a single car break a traffic jam?

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Re: Can a single car break a traffic jam?

#51

Post by arprocter »

logn wrote: post #15

I often try the technique of leaving lots of space and going at a slower, steady pace. One problem is that everyone re-routes around you, and you induce road rage and traffic weaving. The other problem is that unless it's a straight stretch of road, you have no idea what speed is slow enough.

A game I used to play with myself on the highway was to simply try and use my brakes as little as possible - when you see brake lights ahead it's instinctual to also brake yourself, but often if you have a long enough follow distance you can just lift off the gas.

Brake lights being a binary representation of an analogue pedal is another problem, although iirc on some newer cars the lights are brighter/more lights go on the harder you brake

Re: Can a single car break a traffic jam?

#52

Post by notlefthanded »

logn wrote: post #15

I often try the technique of leaving lots of space and going at a slower, steady pace. One problem is that everyone re-routes around you, and you induce road rage and traffic weaving. The other problem is that unless it's a straight stretch of road, you have no idea what speed is slow enough.

Actually it's easier to manage speed and spacing in congestion with a gently curving stretch of road - cars further up are visible so you can anticipate better and slow down earlier/more gradually, reducing jerk. This way too, you won't seem slow to the people behind you. It's not so much going super slow as it is being able to correctly guess the average speed of the road and acting as a damper. This is basically what the article describes btw.

I also like to try and impose a rule of not touching the brakes unless absolutely necessary, and using 20% throttle input at most, that helps with the whole dampening thing.

One last caveat: these techniques only really work for freeways/highways in the developed world. The tragedy of the commons phenomenon is on a whole nother level in places like India or China (se asia in general) or a lot of Latin America or even sixth avenue.

Re: Can a single car break a traffic jam?

#53

Post by cortesoft »

Every time people try to say we can eliminate traffic if we just leave space in between cars, I think of this great article: http://jliszka.github.io/2013/10/01/how-traffic-actually-wor...

TL;DR there is an effective maximum number of cars that can pass through a given point of roadway (about 1 car per 2 seconds per lane). No amount of space-leaving is going to chance that.

Re: Can a single car break a traffic jam?

#54

Post by cortesoft »

matthewowen wrote: post #36
bagacrap wrote: post #30

Earlier quoted context omitted.

The other problem is that this isn't scalable. Imagine a traffic jam that stretches for miles. Now imagine that same jam where everyone has left an extra three car lengths in front of them. You're suddenly using a lot more road per car. Tailgating actually seems like the most efficient use of space to me, provided you tailgate effectively (don't yo-yo).

https://en.wikipedia.org/wiki/Traffic_wave Tailgating is often the _cause_ of the jam.

That really isn't the case in high traffic areas: http://jliszka.github.io/2013/10/01/how-traffic-actually-wor...

Re: Can a single car break a traffic jam?

#55

Post by cpeterso »

GigabyteCoin wrote: post #23
logn wrote: post #15

I often try the technique of leaving lots of space and going at a slower, steady pace. One problem is that everyone re-routes around you, and you induce road rage and traffic weaving. The other problem is that unless it's a straight stretch of road, you have no idea what speed is slow enough.

Truckers (professional drivers) do this all the time. If ever there is a traffic jam on the highway, you will see the big rigs consistently leaving hundreds of feet of space in front of them. They also seem to concentrate in the center lanes of the highway for reasons I haven't figured out yet.

In a traffic jam, wouldn't the alternative to leaving plenty of space be constantly starting and stopping? That seems pretty like a lot of work for the driver in a big rig.

Re: Can a single car break a traffic jam?

#56

Post by tetraodonpuffer »

cortesoft wrote: post #53

Every time people try to say we can eliminate traffic if we just leave space in between cars, I think of this great article: http://jliszka.github.io/2013/10/01/how-traffic-actually-wor... TL;DR there is an effective maximum number of cars that can pass through a given point of roadway (about 1 car per 2 seconds per lane). No amount of space-leaving is going to chance that.

I think you need to read the update #2 in the page you linked, of course you can't create capacity out of nowhere, but if you are in a "phantom jam" situation it does help to "smooth things out" as the page clarifies (which I think is what this article is about)

Re: Can a single car break a traffic jam?

#57

Post by jandrese »

Retric wrote: post #43
cortesoft wrote: post #14

This sort of traffic jam dissipation is only applicable to phantom traffic jams. Here in Los Angeles, traffic jams are caused by too many cars being on the road. At some point, every available square foot of roadway is filled with a car. AI can help limit the amount of extra space taken up by air, but that will only moderately increase the number of cars that it will take before traffic hits. That number of cars will…

Yea, I remember getting stuck in a huge traffic jam and feeling dumb for driving on 66 at rush hour. Until, I remembered it was Saturday. In northern VA traffic is often bad at from around 5AM to 10PM. But, we can have traffic jams at any time day or night 7 days a week. Granted, bad night time traffic is often aided by construction. But, that does not help when your parked on a freeway at 3AM.

I've been stopped due to congestion on 66 at 1AM in the morning. That road is an outright disaster.

Re: Can a single car break a traffic jam?

#58

Post by gerbilly »

I wonder if we'd have as much stop and go traffic if every car on the road was standard.

I drive like this just to avoid using the clutch. I'll basically crawl at the average speed in 2nd gear, until traffic speeds up.

I suspect truckers may be doing it for the same reason, and their gear ratios mean they would have even more gears to cycle through.

Stop and go would be a huge pain for them if they have to come to a full stop.

Re: Can a single car break a traffic jam?

#59

Post by cortesoft »

tetraodonpuffer wrote: post #56
cortesoft wrote: post #53

Every time people try to say we can eliminate traffic if we just leave space in between cars, I think of this great article: http://jliszka.github.io/2013/10/01/how-traffic-actually-wor... TL;DR there is an effective maximum number of cars that can pass through a given point of roadway (about 1 car per 2 seconds per lane). No amount of space-leaving is going to chance that.

I think you need to read the update #2 in the page you linked, of course you can't create capacity out of nowhere, but if you are in a "phantom jam" situation it does help to "smooth things out" as the page clarifies (which I think is what this article is about)

I guess I am just not used to that sort of traffic jam where I am. Here, it is always just 'way too many fucking cars on the road'

Re: Can a single car break a traffic jam?

#60

Post by 0xfeba »

notlefthanded wrote: post #52
logn wrote: post #15

I often try the technique of leaving lots of space and going at a slower, steady pace. One problem is that everyone re-routes around you, and you induce road rage and traffic weaving. The other problem is that unless it's a straight stretch of road, you have no idea what speed is slow enough.

Actually it's easier to manage speed and spacing in congestion with a gently curving stretch of road - cars further up are visible so you can anticipate better and slow down earlier/more gradually, reducing jerk. This way too, you won't seem slow to the people behind you. It's not so much going super slow as it is being able to correctly guess the average speed of the road and acting as a damper. This is basically wh…

> I also like to try and impose a rule of not touching the brakes unless absolutely necessary, and using 20% throttle input at most, that helps with the whole dampening thing.

I do the same. It's funny the frustration this seems to cause other people. Frustration from nothing, if they'd think about it.

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