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The Mythbusters did it! They couldn’t even get up to speed to begin the first experiment because the traffic jam formed naturally.
Hm, this video isn’t available in my country.
There are phantom traffic jams where someone breaks hard and it ripples on for ages. You can see on YouTube.
I find it’s the speeders, tailgaters, and the infuriating few that can’t seem to manage to go at the prevailing speed that cause the waves in traffic. The rest is structural - merges, construction, lane reductions, etc. The aforementioned all cause the slowdowns because they move quickly, traffic tends to follow, and end up constantly hitting their brakes riding the ass of the slower traffic. That starts a wave that ends up with traffic stopping when density is high enough.
You can’t control others moving slower than you want, bitching about lane campers changes nothing, but managing a speed/spacing that allows little or no braking does wonders to keep things moving. If only people would bother to do so.
I used to say “Speeding gets you nowhere, fast” but the irony is lost on anyone that does it.
I think about this all the time while commuting. I yearn so much to teach the drivers this one simple trick!
This is like saying you don’t know how a bottleneck works.
Exactly, it’s entirely because the people in front of you are going slow.
You are thr traffic.
Reaction times of humans.
Traffic is a “thing” because the slowest common perambulator is always in front
It all starts with someone in the passing lane, not passing, and one or more pissed off people behind them :)
The pissed off people trying to get around causes the wave of people behind them to brake and it snowballs from there.
Yeah I drive around 3 hours on the highway every several weeks. Sometimes on my drive, there’s obviously traffic. A lot of times it will be something like rush hour traffic, a crash, construction, etc.
But then like…a good portion of the time when I come to the very front of the “clog”, I find that it is just a blockade of multiple people going incredibly slowly and taking up all lanes of traffic, refusing to move over despite the fact that they are going under the speed limit.
People drive too close to each other, someone has to slow down and then the car behind slows down a bit more. Repeat until you get to the point someone completely stops. Then the next car stops for slightly longer.
If you leave a safe distance then it wouldn’t happen.
Hey I studied this in grad school for a bit, and it really is just “someone does some dumb shit which leads to a cascading wave of additional people doing dumb shit which propagates backwards for miles.” Basically when the offered load is getting close to the maximum load, all it takes is one person aggressively changing lanes to throw that section of highway into gridlock, and it will remain that way until the total integrated traffic flux across that incident boundary again falls below the critical offered load inflection point.
Basically, pick a lane and just stay in it. Maintain proper following distance. Counterintuitively, the following distance should be for the speed you want to drive, so even in traffic it should be like 5+ car lengths even though you are going slow. This is because it reduces the offered load, and once that number falls below the critical point, speeds will increase again. Bumper to bumper traffic basically prevents that from happening because it dampens the ability for a “speedup” wave to propagate.
Of course this is all impossible for humans. All it takes is a few idiots to throw off the balance.
Sad thing is its more than just a few idiots.
The idiots are the majority. So stupidly self absorbed they constantly screw themselves over trying to “get theirs”.
There was a really interesting MythBusters episode where they essentially replicate what you’re talking about. Albeit with an “n” of 1 or 2 and a very small scale, but still interesting.
So basically: 1. Put people in public transport away from the steering wheel, 2) scale back cars use.
Go back to fuckcars with the rhetoric.
“Pick a lane and stay in it” leads to slow drivers blocking the left lane, no?
From a purely traffic load perspective, the whole “fast lane” thing doesn’t make a huge difference, and the aggressive obsession with it is actually a big part of the psychology which creates traffic in the first place. Traffic capacity is generally optimized when everyone is traveling close to the same speed and has enough following distance to safely maintain that speed, which is why speed limits are set for the slowest road users. Just in general, speed does not increase road capacity beyond a certain fairly low limit because it requires dramatically increased following distance, or in the absence of such responsible behavior, it massively increases the frequency of traffic disruption.
The worst case is a few people traveling much faster than the slowest road users, as these few users both take up more space, and cause more disruption. The “fast lane” concept is rooted firmly in an unfortunate behavioral reality and has basically no real scientific basis beyond that. Even if you had perfect robot drivers with perfect reaction time and the ability to see far ahead of themselves, the critical capacity speed only increases slightly because the maximum stoping distance is still limited by rubber and asphalt.
I’m a little confused about the mechanism of the speeders causing the disruption. Is it because when they cut in front of someone closely, it causes the driver to hit the brakes to make more room, thus triggering the chain reaction?
Thats a big part of it, yeah. Theres lots of really good comments about it in this thread.
You have demonstrated why fundamentally humans suck at driving and this problem is unsolvable.
Not because you asked the question but because it’s not intuitive why.
So long as this has to be explained to anyone it can’t be solved.
I’m genuinely curious: are there adverse effects to an arrangement where the right lane is used by large trucks going 90-100 kph, middle lanes used for normal traffic going 120-130 kph and the left lane kept open for faster traffic? As far as I understand, these issues arise when cars go back and forth between lanes all the time, or when cars go slower than the ones behind them without an open lane to overtake them. If you pick a lane and stay in it, you might cause the second issue
Yep! All it takes is one person braking, and then the person behind braking, then the person behind them, and eith each braking the overall speed slows down more and more. It creates a wave of traffic. The wave passes through. The starting point I think moves back further and further.
I think about it a lot while I sit in traffic.
I think the issue is more or less slow drivers. One asshole is going 60 in a 70 in the left lane which caused people to pass them which in turn cause the cascade from the maneuvering around the slow person.
Slow drivers are far more dangerous than people don’t 10 15 over the speed limit.
You are incorrect. You are the cause of the traffic jam lol, literally.
Why is Driving Slower than Other Vehicles Just as Dangerous as Speeding? https://share.google/U82ugU39Gc0XOa55G
A Few Slow Drivers Increase the Number of Accidents https://share.google/SUYjn8eEkNNLe5xBO
Slow Drivers: Dangers of Driving Slow | Allstate https://share.google/7GP2waFViHMUqEJYj
Some times you people don’t even know what you’re downvoting.
Are you trying to suggest that driving at higher speeds is safer than driving at lower speeds? Because that goes against the laws of physics
If people pass quickly, then get out of the left lane, nobody needs to brake and start a compression wave
So an entire third of the road is basically left empty so people can speed?
so even in traffic it should be like 5+ car lengths even though you are going slow.
Other drivers: “It’s free real estate”
Secret is to play the game next to a semi. Some semis kinda do it too by engine braking as they see the wave approaching instead of waiting until theyre close to even slow
slow speeds cause accidents, not speed, it it the sudden stop, the cause of some inbred driver
https://www.mdpi.com/2076-3417/11/9/4278
TLDR: modeling traffic as a gas leads to fairly accurate predictions. If that doesnt mean anything to you, here’s a decent visualization of how gasses move around in a system. In this analogy, each of the gas particles models a car on the road. https://youtu.be/Hr5Baj3lXFA
3 fucking seconds
The answer is a simple 3 second gap.
That’s it, just 3-mississippi (or 3-onethousand) seconds behind the car in front of you and most of the avoidable jams go away.
If you do that, someone will move into the gap. If someone moves into the gap you can slow down to make another gap to them, but then someone else will drive into that gap. I don’t know of any major city where you can maintain a 3 second gap during rush hour.
Even worse, if you ever brake to try to create a gap, you’re likely to cause a traffic jam behind you.
Sure, if everybody did follow the suggestion and allowed a 3 second gap you wouldn’t have traffic jams, but that’s just not human nature, apparently.
You attribute an uneducated, uncivil approach to human nature, but I have been in human queues around the world, and they vary hugely based on cultural and social differences.
What you think is human nature seems to actually be driving culture in your region.
Yesterday I had a swasticar driver actually let me in on a disorderly merge. I was amazed, it was a first. Clue: nothing about Hondas changes people to be better. Tesla and BMW drivers are just shittier at sharing. This is culturally allowed.
Teach people to drive on the right lane unless they want to overtake somebody. Whoever overtakes you on the left won’t drive into the gap because they also want to overtake whoever is driving in front of you.
It’s too late to teach the entire population how to drive differently now.
You’re totally right. It’s a social/culture issue. You doing this on your own isn’t going to do shit. Everyone has to miraculously decide to come together to solve the problem with no one taking advantage. It’s the same reason we can’t do anything about climate change.
At least with climate change, your actions can make things slightly better. It’s not enough to be measurable if only one person does it, but if it’s a tiny pressure in the right direction. But, if you drive in a way that’s too different from how other people drive, you can actually make traffic worse or more dangerous.
Except the person next to you or behind you gets frustrated and cuts you off and you have to hit the brakes and create a traffic pulse.
Well yes, society functions only with cooperation. Uncivil behaviour ends with violence and dismay.
However 3s usually allows for slow adjustments which alleviate caterpillaring.
Only ever have to ask, my friend
Heres an overview shot of a traffic pulse.
One person brakes for no reason which leads to everyone else braking. The pulse travels despite there being nothing there. The longer it can take for someone to start up again also can delay the whole thing.
Iirc, the answer is to have someone drive slowly and let other cars pass. It creates a buffer zone that regulates the flow back to normal pace. Or at least that’s what I remember from New Scientist’s video from like a decade ago.
I used to just idle when traffic moved. Slowed down way before i was even close to the car ahead. Played a game where i was trying to move at a constant speed or max fuel econ. Much less stressful to always be moving than gas/brake every 10s, even if you’re moving 5mph.
Really helps to look 3-4 cars ahead for brake lights.
not slowly, just leave room
It happens when people tailgate. They over react and it causes an according effect.
Or when people drive too aggressively and cut someone off, causing the person being cut off to slam on their brake.
Nope that’s just a negative picture of a guy
