How traffic actually works
jliszka.github.io
How traffic actually works
1–10 of 186 posts
Re: How traffic actually works
#2That was the clearest explanation of traffic I've come across. I'm inclined to buy into it (often it seems no one knows what they're talking about when it comes to traffic).
It also runs counter to what is commonly said about traffic jams. Most people focus on restoring smooth flow by doing things such as driving really slow to create space in front of you. This guy makes the case that "flow" is not really the important factor here.
For the record, I am "that guy" who runs all the way down to the end of the closed lane before merging over. Except I don't consider it an asshole move because as OP points out, I'm making the best use of the road ahead (while allowing fewer people to merge ahead of me)
Re: How traffic actually works
#3Great. I really hope that like 100% of jerk drivers do not find out about this. Never let people merge in front of you...geez man, really?
Re: How traffic actually works
#4Great. I really hope that like 100% of jerk drivers do not find out about this. Never let people merge in front of you...geez man, really?
That was a joke ;) Onramp regulators are the real answer, letting only 1 car merge into traffic at a time at a rate well under 1 every 2 seconds.
Re: How traffic actually works
#5The central assumption for this argument is that the average time between cars is fairly consistent no matter the environment; small changes to this time do not matter.
However, on a congested road very small changes can have huge effects. IIRC, one study showed that a 1% decrease in the number of vehicles resulted in a 28% decrease in commute time.
Re: How traffic actually works
#6The catastrophe theory model seems compatible with the anti-traffic solution to traffic 'standing waves' - by slowing down a little when approaching stationary traffic, allowing that stationary blockage time to 'evaporate', you avoid slowing down below the catastrophic threshold that puts your rear bumper more than 2 seconds behind your front bumper, keeping the road in the higher capacity regime. Same reasoning is why UK motorways signpost 'advisory speed limits' - and some even have variable enforced speed limits - to manage road capacity.
Re: How traffic actually works
#7That was the clearest explanation of traffic I've come across. I'm inclined to buy into it (often it seems no one knows what they're talking about when it comes to traffic). It also runs counter to what is commonly said about traffic jams. Most people focus on restoring smooth flow by doing things such as driving really slow to create space in front of you. This guy makes the case that "flow" is not really the import…
Except I don't consider it an asshole move because as OP points out, I'm making the best use of the road ahead (while allowing fewer people to merge ahead of me)
Which solves nothing but to piss off everyone else behind you who has waited because ultimately someone will let you merge in (which they flat out shouldn't) and said behavior will only encourage others to do so in the future which inevitably will piss off even more people.
Re: How traffic actually works
#8The central assumption for this argument is that the average time between cars is fairly consistent no matter the environment; small changes to this time do not matter. However, on a congested road very small changes can have huge effects. IIRC, one study showed that a 1% decrease in the number of vehicles resulted in a 28% decrease in commute time.
This. I've studied traffic extensively and if you ever wonder how it works, it is actually quite similar to any other network. Imagine road traffic is the same as traffic through your servers. There are hard bottlenecks at various points, but in practice what matters is planning for variability. Real-life situations like someone cutting you off, people rubber-necking, the natural commute tendencies etc tend to be much more impactful. Unlike with servers, you can't just spin up a new lane, and "packet loss" is pretty much unacceptable :)
EDIT: For all you infra folks out there, imagine not being able to dynamically provision resources, no packet loss and worse, the packets can basically do what they want. That includes things like crashing into each other and stopping any other packets from making it through.
Re: How traffic actually works
#9For a blog post that that claims to explain "How traffic actually works" I find it disappointing that the author doesn't even briefly touch on the dynamic properties of this problem.
No, this is not how traffic works, the model is much more complex and you're missing very large dynamic effects.
Re: How traffic actually works
#10That was the clearest explanation of traffic I've come across. I'm inclined to buy into it (often it seems no one knows what they're talking about when it comes to traffic). It also runs counter to what is commonly said about traffic jams. Most people focus on restoring smooth flow by doing things such as driving really slow to create space in front of you. This guy makes the case that "flow" is not really the import…
Smoother traffic flow (as opposed to stop-and-go) may get you to your destination slightly slower due to added distance between cars, but that is not the only consideration. Gas mileage and car wear-and-tear are improved (and I suspect safety as well) when the driver is not alternately stomping on the accelerator and brakes.