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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?

#101

Post by Tiksi »

seanp2k2 wrote: post #65
arprocter wrote: post #51

Earlier quoted context omitted.

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…

IMO if you have to brake on the freeway, someone made an error. Cool about brake lights; I've wondered for years why they don't do this. I knew about some newer cars flashing the hazard lights in a very hard stop, but didn't know any were doing brake light meters. Any idea which specific models? I'd love if they standardized the messaging across brands and countries; imagine a new mustang where 1 vertical bar on each…

New Jersey transit buses do something similar. For light braking the amber lights come on, for harder braking the actual brakes lights do.

Re: Can a single car break a traffic jam?

#102

Post by SilasX »

rando18423 wrote: post #99
SilasX wrote: post #40

Earlier quoted context omitted.

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…

So the poor person who needs to get to the doctor should take the slow lane, and the rich person who wants to get to the next bar faster should take the fast lane? Public utilities INTENTIONALLY are not and should not be run according to the principles of profit maximization.

The poor person should take the bus, which could actually be a fast option if the streets weren't choked at critical times. That's what a sane utility looks like. (If they're not choked, no congestion charge.)

I'm not a big fan of the mentality that the transportation system should suck just so we can avoid the rich have better options than the poor. Taken seriously, that would mean a ban on air travel because the poor can't have as much.

If you meant emergency vehicles, those always have priority :-p

Re: Can a single car break a traffic jam?

#103

Post by ec109685 »

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…

If the cars were able to travel faster (by organizing themselves to flow more optimally), they wouldn't all need to be on the road together.

Re: Can a single car break a traffic jam?

#104

Post by jemfinch »

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…

> 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 be reached, easily.

The thing to keep in mind is that AI can limit the extra space between the cars as well as increase the speed those cars can safely travel. The cars will spend substantially less time on the road because they'll be going faster. Double the speed and you've converted a 60 minute commute into a 30 minute commute, doubling the number of commuters the roadway can support even if you don't adjust inter-car distance art all.

Re: Can a single car break a traffic jam?

#105

Post by jeremysmyth »

jemfinch wrote: post #104
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…

> 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 be reached, easily. The thing to keep in mind is that AI can limit the extra space between the cars as well as increase the speed those cars can safely travel.…

Don't forget Amdahl's law though. You might be able to optimize away the reaction time with good AI, but you can't optimize away mechanical factors like engine failure, tire grip, and road surface friction. This affects the maximum speed and traffic density just like a human's reaction time.

This means that if one car in a densely packed column fails (blowout, engine seizure, ...) then the car immediately behind it is still subject to its mechanical ability to avoid a collision (swerve into empty space or brake to a hard stop at speed) no matter how fast it reacts.

Re: Can a single car break a traffic jam?

#106

Post by arprocter »

seanp2k2 wrote: post #65
arprocter wrote: post #51

Earlier quoted context omitted.

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…

IMO if you have to brake on the freeway, someone made an error. Cool about brake lights; I've wondered for years why they don't do this. I knew about some newer cars flashing the hazard lights in a very hard stop, but didn't know any were doing brake light meters. Any idea which specific models? I'd love if they standardized the messaging across brands and countries; imagine a new mustang where 1 vertical bar on each…

I want to say it was first introduced by either BMW or Mercedes.

I've seen Porsche races on TV where you can see a strobing effect, although LEDs sometimes look strange on video

Re: Can a single car break a traffic jam?

#108

Post by 0xfeba »

seanp2k2 wrote: post #64
0xfeba wrote: post #60

Earlier quoted context omitted.

> 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.

"But I want to go fasterrrr! Why doesn't he goooooooo?!?!?" One time, a man and a lady in a Harley Davidson edition F150 got so mad at my for doing this that they were both screaming at me through my open sunroof, threatening to get out and physically assault me etc. They kept yelling at me to "learn how to drive". It as grid-lock traffic and we'd have minutes at a time of complete stoppage. That was a pretty awkward…

Yeah I've had that a couple times. Once was a honk (I can only assume was) because I wasn't tailgating--yet we were moving at the same speed, so the driver swerved from behind me to the side and then in front--then slammed on their brakes.

The other time was after cruising during a lot of short stop and go intervals (so it was easy to judge crawling speed, that is to say). I eventually switched to the lane I needed and the guy who was rubberbanding behind me the entire way (pretty much going 1-10-1mph constantly instead of just sitting at 3 like me) pulled next to me and shook his head. I had a good feeling why, so I rolled down my window as we came to a stop next to each other at a light and asked if there was a problem. He said, "You drive like a dumb ass". "Oh, I do? Please tell me what I was doing wrong so I can improve". "You just drive like a dumbass". "No really, you seem like you know a lot about driving, please enlighten me". And he rolled up his window, the light turned green but he accelerated before the car in front of him had a chance to go (perhaps to get away from me, I'm 6'2" and 250lbs.), and then slammed on his brakes again...

Dunning-Kruger, if you ask me.

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