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.
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.
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?
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 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.
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
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
https://www.youtube.com/watch?v=Rryu85BtALM
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.
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?
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