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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?

#31

Post by ahlatimer »

blakeyrat wrote: post #17
noonshine wrote: post #12

I have adaptive cruise control in my Subaru Legacy and I have often wondered what will happen when more people have ACC. Or even if I were following another car exactly like mine - would the lag time grow exponentially with more intense stop/go or would it even out? Or does it depend on how well the car implements it?

The adaptive cruise control in my Ford turns itself off if the speed is low enough-- which on Seattle-area freeways happens pretty often. So I stopped trying to use it.

The Subaru one stays on until you come to a complete stop. Even then, it's still "on" in a way, since it'll hold the brakes, but you have to flick up on the cruise control switch to get the car to start moving again. It'll also notify you if the car in front has started moving again and you haven't done anything (with or without ACC on). It's on my girlfriend's car, so I don't use it every day, but it has been nice the times I've driven it in traffic.

Re: Can a single car break a traffic jam?

#32

Post by StillBored »

This theory has been running around for a a few decades now. But a couple years ago I read a paper where they were studying traffic jams, and the conclusion is that elastic traffic is the problem, and this technique does nothing really to solve the problem. Instead simply maintaining the exact same spacing in front/back of your vehicle does a much better job of avoiding and clearing traffic jams.

Re: Can a single car break a traffic jam?

#33

Post by seizethecheese »

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.

Semi-trucks are generally not allowed in the left lane on the freeway, and the right must be a nightmare of merging for semi-trucks in traffic.

Re: Can a single car break a traffic jam?

#34

Post by maxerickson »

paulmd wrote: post #26
cft wrote: post #16

Earlier quoted context omitted.

AI will eliminate truck night stops, allowing them to be driven 24/7. Hopefully more trucks will be moving at night. That should reduce the jams.

Increasing the efficiency of a process also tends to paradoxically increase its utilization (Jevon's Paradox). So it's entirely possible that automated trucking will actually increase total traffic volume. Still though, even a few vehicles "eating traffic waves" can break up a traffic jam. I've heard the number put at 3-5% of traffic being self-driving would prevent phantom traffic jams. So overall I would say that s…

Tariffs. If people want access to a congested zone, charge them for it. Dynamically adjust the tariff based on the level of congestion.

Of course people hate this and wail that it isn't fair, but it is among the more fair solutions to the immediate problem and inflicting traffic jams is probably not a good way to address economic inequality.

Re: Can a single car break a traffic jam?

#35

Post by elchief »

The trick is to leave enough room in front of you so you don't have to jam the brakes, but not enough room that some fucker will pull in front of you.

I also try to jump into the left lane at an intersection stop, if there's no left turner, to let people turn right

Re: Can a single car break a traffic jam?

#36

Post by matthewowen »

bagacrap wrote: post #30
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.

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.

Re: Can a single car break a traffic jam?

#37

Post by serge2k »

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.

> One problem is that everyone re-routes around you, and you induce road rage and traffic weaving

Probably a good indicator you are going too slow.

Which is okay, just please, please, PLEASE stay in the right lane.

Re: Can a single car break a traffic jam?

#38

Post by serge2k »

elchief wrote: post #35

The trick is to leave enough room in front of you so you don't have to jam the brakes, but not enough room that some fucker will pull in front of you. I also try to jump into the left lane at an intersection stop, if there's no left turner, to let people turn right

> not enough room that some fucker will pull in front of you.

why does it matter, most of the time?

Re: Can a single car break a traffic jam?

#39

Post by Jarwain »

bagacrap wrote: post #30
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.

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).

The jam might not necessarily occur in the first place if Everyone leaves three car lengths in front of them while in motion. Packing together at super slow or standstill traffic is okay. The goal is that traffic continues to flow at a reasonable pace; space between cars doesn't necessarily matter when determining how long it takes to get from point A to point B.

Re: Can a single car break a traffic jam?

#40

Post by SilasX »

maxerickson wrote: post #34
paulmd wrote: post #26

Earlier quoted context omitted.

Increasing the efficiency of a process also tends to paradoxically increase its utilization (Jevon's Paradox). So it's entirely possible that automated trucking will actually increase total traffic volume. Still though, even a few vehicles "eating traffic waves" can break up a traffic jam. I've heard the number put at 3-5% of traffic being self-driving would prevent phantom traffic jams. So overall I would say that s…

Tariffs. If people want access to a congested zone, charge them for it. Dynamically adjust the tariff based on the level of congestion. Of course people hate this and wail that it isn't fair, but it is among the more fair solutions to the immediate problem and inflicting traffic jams is probably not a good way to address economic inequality.

Agree. Tolls (assuming they means the same thing as tariffs) can also create the critical mass necessary for commuter bus lines to work, thereby allowing people to spend only a little more than they do now on commuting but get there faster since the roads are cleared. (The per person effective toll would be lower on a bus, even if they are charged by size.)

But they would have to be much higher than in most proposals, and they should be much lower or non-existence during hours when they're not choked despite the zero price.

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