The very many questions-not-worth-their-own-thread question thread XXV

[Cheezy the Wiz]

Does traffic flow ever obey fluid dynamics? I thought it didn't. Traffic is composed of discrete units (quanta, if you like), whereas fluid dynamics is usually modelled by continuous variables. Isn't it? I don't know for sure, but I thought it was.

At certain volumes it does. Other times it does not.

Here is an interesting discussion of attempts at applying models to traffic patterns.

Some of the predictions of fluid mechanics are completely backwards when it comes to traffic though. For example, when a bunch of cars enter a bottleneck in the road their drivers tend to slow down and drive more carefully to avoid a wreck. The particles modeled by fluid dynamics would on the other hand speed up as they push each other through a narrow pipe.

Cars don't physically push each other, though, and don't have a constant pressure behind them forcing them through the pipe. They proceed at their own pace.

Yeah, that would be the jerks that try to fly by on the median and cut in right at the beginning of the bottleneck. You know, the ones you have a moral obligation to swerve out in front of if possible.

 

[Borachio]

Yeah, that would be the jerks that try to fly by on the median and cut in right at the beginning of the bottleneck. You know, the ones you have a moral obligation to swerve out in front of if possible.

That'd be me! Watch out, I'm coming through! I'm in a hurry and on a mission.

Pull out in front of me, and there'll likely be a messy crash. Still, it's your choice.

(Look. Just because most drivers have no idea how to filter sensibly two lines into one, there's no reason I should wait patiently at the back of queue, is there? With an empty lane just begging me to occupy it.)

 

[bhsup]

It's not a lane! but I'm not worried because if you were over here, you'd probably be trying to go on the median on the OTHER side of the road anyway.

 

[Borachio]

Oh right.

Years ago, we used to have three lane highways - not a dual carriageway but just three lanes with the middle lane supposed to be used just for overtaking. They were fun! And got fazed out of use, for some reason (probably related to the number of head-on accidents).

I miss them.

 

[Farm Boy]

Those roads(and highway speed country roads with enough room for 1 and 1/2 cars) certainly do have that pucker factor that lets you know you're alive!

 

[Cheezy the Wiz]

(Look. Just because most drivers have no idea how to filter sensibly two lines into one, there's no reason I should wait patiently at the back of queue, is there? With an empty lane just begging me to occupy it.)

Are you even British?

 

[bhsup]

Hey, Farmboy! You need to start the "The very many questions-not-worth-their-own-thread question thread XXVI" thread!

 

[Borachio]

Are you even British?

I think so. Well, English anyway.

But I was a professional driver for twenty years. So that's probably coloured my attitude towards traffic somewhat.

Otherwise I conform strictly to my national stereotype, queue-wise.

 

[Farm Boy]

Hey, Farmboy! You need to start the "The very many questions-not-worth-their-own-thread question thread XXVI" thread!

In the interest of quality, I'll punt to you if that isn't terrible form. Otherwise I'll try and get to finding the links and whatnot sometime Monday or Tuesday.

 

[bhsup]

Actually then it falls to Cheezy, but thanks for thinking of me.

 

[Hygro]

Like I said, if there aren't enough cars on the road to prevent them moving at 75, I wouldn't consider it to be congested.

Congested is all you. We were talking about "heavy traffic"- so heavy traffic to you is only defined by cars going slower than the speed limit as a function of traffic density, and not a function of car density itself.