The Science of Traffic Jams

[Dr_Evil_Mouse]

I remember timouse telling me once of a study he'd seen where traffic jams were being interpreted in terms of water dynamics (with the proviso that the metaphor ultimately failed because water molecules aren't inherently stupid or self-absorbed). I just saw this link, though, on Rick Mercer's site, which will no doubt give lots to mull over the next time the traffic on the 417 suddenly goes glacial.

The Science of Traffic Jams

When a car in front does something unusual, drivers often respond by hitting the brakes. That in turn makes the next driver brake. Soon, a wave of commuters are flashing red brake lights.

Humans typically take 3/4 of a second to slam on the brake pedal. Talking on a cell phone can slow response time even more. The delayed reaction creates instability in an otherwise steady stream of traffic.

That's when cars end up bumper to bumper.

"The slow reaction time means people brake more than they should have to," Davis said. "Unnecessary braking—too much slowing down—causes the jam to form in some instances."

Physicists tend to think of the build-up of traffic like water turning to ice.

Smooth traffic moves freely like water. When water freezes and turns to ice, it requires more energy, in the form of heat, to melt back into water. Similarly, it takes more time and work to get gridlock going again.

Davis presented his research about how to decongest the roadways at the American Physical Society meeting in March.

Automatic solution

To cut down on bottlenecks in the future, cars could come equipped with adaptive cruise control. The automatic system responds more quickly than human beings.

Interesting that their solution involves removing the human element .

[timouse]

honk. punch. gas. honk. punch. brake. honk. punch.

mmmm....traffic....

[SmoothedShredder]

Usually when I drive... I try never to come to a complete stop... that means I'm really slow coming up to red lights, often putting it in neutral to coast to the light, saving my brakes to boot... but I'm pretty good at timing it that I get within 2 or 3 metres of the car in front before they let go of their brakes to get going. I don't want the guy to think I holding them up, and if I reach the car in front of me before it starts moving they don't really have much to complain about unless of course they wished I didn't exist and wasn't even there in the first place. I've had 3 to 4 cars pass me on the left in order to slam on the breaks and wait at the red, which I eventually re pass on the right... I also 'push' off tailgaters by slowing down enough that they have to down shift... then bam, I down shift, hit the gas and jump ahead... this either gives them enough room to pass me properly on the left (calling me a idiot, or asshole or whatever when the do it properly (downgeared and accelerating into the passing lane), or a couple seconds before we do it all again... I used to 'fight' traffic... but it really made me mad, and it's very irrational... I mean, I didn't build the roads... I never master the engineering of the automobile... I didn't import the gas... It really is a privilidge to drive... and there are alot of spoiled little brats out on the roads... I used to be one, now I jut play within the rules.

One benefit of this driving technique is that I often end up at the front of a red light, at which point, I have no objection turning it into a drag race where first to the speed limit wins. I never lose... usually leaving some slow dense person on a cell phone clogging up the left lane, and giving me free access until the next phase of cogestion.

I also have no objection speeding 10 - 20 over when I'm infront when in city mode (highway is another beautiful story!)... it gives all the dense drivers lots of space behind me to 'work things out', and if there is a cop hiding, he usually has to wait for the mess behind me to pass before he/she can zoom out to catch me, at which point (thanks to the odds), he probably would of seen someone else doing something more risky/dangerous than my techniques, and closer for the cop to catch when they actually enter traffic. Also starting at the front gives me the best chance of seeing speed traps coming up... and 11 years of driving, and only one speeding ticket when I was 16 where I was trying to get my girlfriend home on time for her 1 o'clock curfew speak for itself... knock on wood.

I'd say atleast 50% of the people on the roads drive in such away that makes 'inefficent' to drive... When faced with a decision to drive in such a way that one is helping the flow of traffic vs. helping out only themselves, or an opportunity to make traffic flow better vs. 'saving a couple seconds' for oneself... this 50% usually choose the latter.

[AD]

and 11 years of driving, and only one speeding ticket when I was 16 where I was trying to get my girlfriend home on time for her 1 o'clock curfew speak for itself... knock on wood.

ahem. you only avoid speeding tickets because you claim your car is slow and make me lead. and then i get nabbed. or you burn across new brunswick in 3 hours at 180, then when we switch drivers i get pulled over doing 120.

but other than that, good points.

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[Birdy]

wow.

you guys have the science of driving all mapped out.

i'm irrational and in all of that, really have no driving style or science to me. when i'm in a hurry, i ride cars and honk horns and get super pissed off and yell out my windows. other times i cruise leisurely at 60 km/hr in an 80 zone and marvel at my surroundings. i normally like to be at the front of a red light though.. my pet peeve is people who stop with the intent to go straight in the right hand lane at a stop light. HATE THAT.

i also hate driving in Calgary. my road rage comes out in full force in that city.. the city of crawling cars and school zone after school zone after school zone and stupid photo radar and drivers who become extremely pissed off if you're going ten kms over the speed limit. my irish temper comes out in full force in that city.

[SmoothedShredder]

you only avoid speeding tickets because you claim your car is slow and make me lead. and then i get nabbed. or you burn across new brunswick in 3 hours at 180, then when we switch drivers i get pulled over doing 120.

I NEVER would of said my car was slow... I was driving that way because the flow of traffic was such that the probability of getting nabbed was high... you got caught... I also remember you tailgating alot and didn't really feel too bad about you getting a ticket... except for the fact you're my friend, and I know that the speeding ticket probably meant a few less shows you could attend...

When I was doing 180 through NB (I thought I hit 200 a couple of times ), there was NO ONE around me... when I came up to a car... I slowed down to 140 - 120... and I time it so I make the move just after one of those police u-turn things. There is a method to the madness...

[SmoothedShredder]

Hehe, remember our first trip to Bonnaroo... my muffler broke right when we hit Toronto, so I went the entire way there and back with a huge hole in the muffler making it LOUD, and it taped up cause it was rattling like crazy. I loved the look on the faces of the Kentuckians when I pulled up with the loudest SON OF A BITCH on the road, and it wasn't even a domestic car!

[AD]

tailgating? no sir.

when i got nabbed in NY i was the lead car in a line of about 6 or 7 doing my speed (11 mph over the limit). when i got nabbed in QC with you i was coming out of a rest stop, and i'm pretty sure the cop was tailgating me.

anyways. i haven't got a ticket in a while. so that's good.

FYI, my car has never gone faster than it did when you were driving it in the maritimes.

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[AD]

Hehe, remember our first trip to Bonnaroo... my muffler broke right when we hit Toronto, so I went the entire way there and back with a huge hole in the muffler making it LOUD, and it taped up cause it was rattling like crazy. I loved the look on the faces of the Kentuckians when I pulled up with the loudest SON OF A BITCH on the road, and it wasn't even a domestic car!

yeah, and you kept telling me to speed up!!!

[SmoothedShredder]

hmmm? I think you misinterpreted my car language... I kept hoping cars finding 'calm zones' and waited paticiently for you to catch up... no rush, just do it safely, and stick together without tailgating (remember our third car last year... I refused to lead cause of their desire to CONSTANTLY tailgate, even at night when the lights are really bright, but they admitted they were so worried about being left behind (I guess every one can't be Geography majors )and to their discredit, they did end up in Arkansas after the last night when we went ahead to memphis to miss WSP) But still, I'm a believer of what my CAA instructor has told me "Every accident is preventable", and I feel the same way about speeding tickets. I've also bolted by cops behind bridges at 140 on the 401 on my numerous trip between Toronto and Ottawa "that year" and since, but when I do it, there's NO ONE around me... and I think they can recognize that as a factor to consider how someone handles speed.

[hamilton]

my pet peeve is people who stop with the intent to go straight in the right hand lane at a stop light. HATE THAT.

I agree. I get stuck behind these people on a daily basis. Some people have no consideration whatsoever. Sometimes it can't be helped, but I've seen many people move from left lane to right lane for no apparent reason other than to be first in line at the light, thus denying anyone else an opportunity to make a right on the red light. Fuckers.

Edited May 8, 2006 by Guest

[payce-ley]

Google Map supposedly good for avoiding highway traffic jams around Toronto

haven't put it to the test

Edited May 9, 2006 by Guest
yes