
The Physics Behind Traffic Jams - netvarun
http://www.smartmotorist.com/traffic-and-safety-guideline/traffic-jams.html
======
seanp2k2
>"It was dusk, the headlights were on, and I was going down a long hill to the
bridges. I had a view of miles of highway behind me. In the other lane I could
see maybe five of the traffic stop-waves. But in the lane behind me, for
miles, TOTALLY UNIFORM DISTRIBUTION. I hadn't realized it, but by driving at
the average speed, my car had been "eating" traffic waves. Everyone ahead of
me was caught in the stop/go cycle, while everyone behind me was forced to go
at a nice smooth 35MPH or so. My single tiny car had erased miles and miles of
stop-and-go traffic. Just one single "lubricant atom" had a profound effect on
the turbulent particle flow within the "tube.""

When I try this, most other people have no idea what I'm doing and/or are
stupidly greedy and go "OMG A GAP" and rush into it. I'll also typically have
people behind me honking / flashing their headlights at me, as they're equally
clueless. I've had one dude and his wife, in a Harley Davidson edition F150
actually roll down their window and scream at me for "not knowing how to
drive".

I drive a 6spd stick too, so the stop/go is even more painful. I try to be
that "lubricating atom" both for my sanity and to ease the jam, but the
collective inability of other drivers to think beyond "OMG MAKE AS MUCH
PROGRESS AS SOON AS I CAN" greatly inhibits my efforts.

TL;DR traffic jams are caused because people are greedy and short-sighted in
their greed. It's not really different from all of the other big problems with
humanity.

~~~
Nimi
I beg to differ, and that's a criticism I also have for the OP:

From my humble observations, traffic jams are caused because too much traffic
(x cars/sec) flows into a bottleneck, i.e. something that can't allow x
cars/sec to pass through. Whenever I get into a traffic jam, I play "spot the
bottleneck" to ease my boredom, and so far I haven't found a case where there
was none.

Transient traffic jams like the OP described seem to get solved by people
accelerating as much as they can once they're past the jam. If there's no
bottleneck ahead, they're indeed transient.

~~~
artmageddon
Bottlenecks caused by an accident or merging lanes on a motorway are one
thing, but I've seen traffic jams where the bottleneck was a disabled car that
was well clear of the road, or the police have pulled someone over. In those
instances there's no good reason to have a jam.

~~~
Nimi
Well, there's a reason, it doesn't matter if it isn't good: other curious
drivers. Here in Israel, traffic reporters on the radio routinely implore the
listeners not to slow down and take a look, since it causes jams.

My point is, whatever causes a segment of the road to only allow x cars/sec
will cause a bottleneck if there are more than x cars/sec incoming flow,
regardless of whether it is inherent or not.

------
AndrewKemendo
Some years ago (2008) research (1) demonstrated that traffic jams were chaotic
dynamical systems and given a certain traffic density would be inevitable
based on the variability of drivers. Here is a video demonstrating as such:

[http://www.youtube.com/watch?v=7wm-
pZp_mi0](http://www.youtube.com/watch?v=7wm-pZp_mi0)

I always found this fascinating. My hope is that the driverless car idea will
take off in earnest and normalize the variability between drivers, making for
a much more rational/logical commute.

1:
[http://iopscience.iop.org/1367-2630/10/3/033001/fulltext/](http://iopscience.iop.org/1367-2630/10/3/033001/fulltext/)

~~~
seanp2k2
The problem with driverless cars is that not everyone will switch to
driverless cars overnight, so the driverless cars will have to deal with
drivers. Ever had your GPS tell you to get in the wrong lane? I'd love to see
how well a Google self-driving car gets on trying to get over 4 lanes in a
mile in gridlock traffic. I live in the bay area, and you only ever see the
self-driving cars out when traffic is very light. It'll probably be a "better
cruise control" long before we have cars that we can get into, program a
destination, and sit back while the car takes us there. It's a nice dream, but
it seems 10+ years from being viable.

~~~
derekp7
For the "better cruise control" aspect, I can envision the user interface
giving the drive the illusion of driving in a rut in the road. So that when
the car drifts to one of the lane edges, there would be a slight tug on the
steering wheel similar to what you would feel if the road was cupped -- but
something you can easily overcome if you intend to.

------
teuobk
Contrary to one of the recommendations in the article, the Minnesota
Department of Transportation recommends _against_ merging early, and instead
has made a large public-education effort (including signs at merge points) to
encourage zipper merging:

[http://www.dot.state.mn.us/zippermerge/](http://www.dot.state.mn.us/zippermerge/)

More discussion:

[http://www.drmomentum.com/aces/archives/003800.html](http://www.drmomentum.com/aces/archives/003800.html)

~~~
Tloewald
Zipper merging works far better in practice than the early merging proposed in
the article. To begin with you usually can't see where the land ends well
enough to merge early, and once things slow down you're screwed. Zipper
merging works great if everyone expects everyone else to do it. The problem in
the US is that people trying to zipper merge are punished by drivers who think
early merging is polite.

~~~
dwd
Most drivers (at least in Australia) will be courteous in this way. Where it
breaks down is that the point of merging tends to move backwards, eventually
to a point where drivers are merging quite early, sometimes to the point where
arriving vehicles don't even know a merge is occuring. What then happens is
drivers push ahead and attempt to start a new merge close to the
barrier/traffic cones again. However no one wants to merge twice and see these
restarts as skipping the line.

The OPs main point of leaving larger gaps might solve this, but generally gaps
will fill and you are then back to gridlock.

~~~
Tloewald
This accords with my own experience driving in Sydney, where the need to merge
is frequent, but not Canberra, which has more more US-like freeway system.

~~~
dwd
Brisbane had a few bad years of building insane combined on/off ramps that
tend to block frequently as everyone needs to be in that lane but with three
or four lanes of traffic. Hale Street as you pass Suncorp Stadium is a
particularly bad one.

------
networked
The article shows what looks like a time-continuous microscopic traffic flow
model ("microscopic" means that the model accounts for individual cars as
opposed to fluid-like "traffic streams"). There also exist cellular automaton-
based models like the two-dimensional Biham–Middleton–Levine model [1] or the
one-dimensional rule 184 [2] that can also show fascinating behavior but are
much easier to program a computer simulation of and to alter (say, introduce
different kinds of vehicles to).

Check out the videos on the Wikipedia page to which I've linked, especially
[3], to see what I mean. In those videos the blue dots are trying to get from
the top to the bottom while the red ones are trying to go from the left edge
to the right edge of an "intersection".

[1]
[https://en.wikipedia.org/wiki/Biham%E2%80%93Middleton%E2%80%...](https://en.wikipedia.org/wiki/Biham%E2%80%93Middleton%E2%80%93Levine_traffic_model)

[2]
[https://www.wolframalpha.com/input/?i=rule+184](https://www.wolframalpha.com/input/?i=rule+184)

[3] [https://upload.wikimedia.org/wikipedia/commons/1/18/Biham-
Mi...](https://upload.wikimedia.org/wikipedia/commons/1/18/Biham-Middleton-
Levine_traffic_model_self-organized_to_a_periodic_intermediate_phase.ogv)

------
socillion
Original copy at [http://trafficwaves.org/](http://trafficwaves.org/)

A video from there, omitted from OP:
[https://www.youtube.com/watch?v=iGFqfTCL2fs](https://www.youtube.com/watch?v=iGFqfTCL2fs)

OP is a cut-down version of this site, which has been up for a decade or two.
I'm curious if it's a legitimate copy.

------
freework
The solution to traffic jams is to have a dynamically calculated speed limit
based on the density of the traffic flowing through it. A car going 60mph down
the highway needs 50 feet in front and 50 feet in back between it and the
other cars (for braking distance). When that same car is going 20 mph, you
only need 10 feet in front and back. Therefore, to support more cars, speed
needs to slow down. You could have a device that counts the amount of cars
entering the highway, and then an algorithm could assign a speed limit for a
section of the highway. In the middle of the nigh, theres no one else on the
road, so the speed limit will be very high. During rush hour the speed limit
could be as low as 15mph. This would make merging easier since you're going
slower.

You wouldn't think that lowering speed limits would easy traffic congestion,
but it would. Its a counter-intuitive, so it will never be implemented
anywhere.

~~~
pmenage
It's already implemented on the M25, the orbital motorway around London. It
gets used quite frequently to slow commuter traffic down from a limit of 70mph
to as low as 40.

There's a particular incentive there because being a loop a bad traffic jam
could (theoretically - I'm not sure it's ever happened) stretch so far that
its head and tail collide. Plus, of course, the fact that the M25 was
demonically planned in the shape of the mystic sigil Odegra, from the alphabet
of the Black Priesthood of Ancient Mu.

~~~
lostlogin
It's done in central Auckland too.

------
Too
It's the same as when approaching a red light or any other intersection. If
you drive all the way up and make a full stop you will have to accelerate from
0 once you get green. If you slow down when you see the red you can be able to
roll into the intersection with speed just as the light switches to green
effectively giving you a 30km/h headstart or more.

You leave the intersection faster and you save gas by not accelerating. I
don't understand why more people don't do this very simple move. The tricky
part is timing the switch perfectly which is almost impossible, instead you
should just slow down more and more and more and try to never ever fully stop
the car fully.

~~~
3minus1
> just as the light switches to green effectively giving you a 30km/h
> headstart or more

Please be careful with this. If you immediately occupy an intersection after a
light turns green there's a chance you'll get blindsided when another car
decides to run a red.

------
afterburner
A shame "rubberneckers" were mentioned (even if in passing); it always bothers
me when "rubberneckers" are blamed for a slowdown, despite that it may simply
be the long-term wave slow-down after the incident (as also discussed in the
article). The reason it bothers me, especially when it's mentioned in a
traffic report, is it gives everyone a little easy road rage "blame the bad
driver" excuse when everyone just needs to chill out and realize this will
only cause a few minutes delay at worst.

It's also futile to try to "train" everyone to overcome these little wave
effects. All you're going to do is give some people an excuse to rage at
others about their "inefficient" driving. Just keep your distance, follow the
rules of the road, and put on some good music/audiobook/podcast/etc. You will
get there eventually, and one day better self-driving cars or mass transit
will make this frustration moot.

(Note that even if self-driving cars aren't specifically programmed to solve
the wave effect, it won't matter because you'll be too busy watching TV or
reading to give a damn. I'm all for efficiency, but having commuted by car for
years, it's not about these little things anyways, it's the sheer time spent
that is the worst thing (and damaging on a personal level), and traffic
accidents truly do block traffic anyways.)

~~~
jakejake
I think it's easy to call everybody rubber-neckers, but in reality when you
pass a big mess of police lights or anybody stopped on the side of the road, I
consider it a bit of a courtesy and safety to slow it down a little and, if
possible, merge into a lane so you don't do a "fly by" at full speed with
somebody standing at the side of the road.

------
jasallen
"ON THE RIGHT >>>>> DRIVERS WITH UNUSUAL BEHAVIOR: THEY ENCOURAGE OTHERS TO
MERGE AHEAD OF THEM, AND THEY TEND TO MAINTAIN LARGE SPACES AHEAD, EVEN IF
TRAFFIC SLOWS TO A CRAWL. MERGING IS EASY. SEE HOW MUCH FASTER THEY GO?"

This is misleading 1)The actual throughput of cars through the constriction
_even in the animation_ is only slightly faster despite 'apparent' better
speeds.

2)The animation does not account for drivers re-assuming their previous
following distance. Regardless of whether your 'comfort' distance is half car-
length or 5 car lengths, you will eventually resume it. Leading to a slowdown.
The advice, and animation seems to assume both that we've merged (onto the
highway in the first place) at a rate that can absorb those driving distances
without additional slow-down _and_ that we won't resume our previous driving
distance (after merging past the constriction). In short, its moved the
problem and then shown a window into the part that was improved.

*edit: added parenthetics to improve clarity

------
mwexler
This appears to be a prettier version of William Beaty's work at
[http://trafficwaves.org/](http://trafficwaves.org/) which is well worth the
read. I send this link out multiple times a year to friends, because it
advocates (and shows some proof for) some simple driving changes that can
substantially reduce traffic: Leave space ahead of you, and let folks cut in
if they want. Given the chaotic pattern of traffic and drivers, these simple
habits appear to reduce (but never eliminate) traffic jams.

~~~
manojlds
Just to be clear, both are by the same person.

~~~
mwexler
Indeed, the article is credited to him, thanks for pointing that out (missed
that!). But the original posted site ("smartmotorist") didn't seem to have any
credits, so unclear if it's a rip-and-post or if Mr. Beaty was part of
"smartmotorist". Regardless, I think Trafficwaves.org gives more info, so
wanted to share.

------
dirkgently
I have been experimenting a bit whenever I am stuck in the traffic. The goal
is not to come to a complete stop. So, in order to do that, I keep long enough
gap in front of me while the traffic is crawling, and keep a low speed such
that I do not get too close to the car in front (in which case, I have to come
to a complete stop).

Just by doing that, the car behind me can also just follow me at the same
speed without coming to a complete halt.

I just hate sitting still on the highway. This game keeps me entertained while
also helping a few cars (if not all) behind me.

The best place to see this effect is in a tunnel (say, Holland tunnel, where
switching lane is not allowed). Just one car maintaining a low speed with
enough space in the front can make the whole lane flowing so easily.

I just don't understand people who would accelerate and the brake, and repeat
this until they are out of the traffic. Not only you are causing yourself a
lot of anguish, you are also not helping others, nor your car.

~~~
enraged_camel
>>I just don't understand people who would accelerate and the brake, and
repeat this until they are out of the traffic. Not only you are causing
yourself a lot of anguish, you are also not helping others, nor your car.

Accelerating and braking is also a fantastic way to waste gas.

------
ChrisNorstrom
Yeah, Traffic Waves. There's no cure. They've been studied, documented, they
have many causes but there's no way to get rid of them unless all the cars on
the highway are autonomous and self correcting.

Once a highway increases past 2 lanes they are inevitable as people from the
far left lanes have to merge right to get to their exit and the 2 right lanes
than can normally hold 20 cars with a 1 car space in between all of them now
have to cope with 35 cars. The cars in the left lane can't merge in time to
get to their exit so the far left lanes start slowing down as well.

There are a LOT of causes, from bunching (cars driving too close together) to
pattern breaking (cars slowing down to look a pulled over cop), to merging, to
accidents, to bottlenecks, to over-crowded exits, etc...

The only way to provide some relief is for ALL drivers to travel in
groups/packs with large gaps in between the groups/packs. The gaps can obsorb
slow downs.

~~~
covercash
>The only way to provide some relief is for ALL drivers to travel in
groups/packs with large gaps in between the groups/packs. The gaps can obsorb
slow downs.

Whenever I'm stuck in Philadelphia traffic I try to do this and it seems to
make a difference. I've even thought about getting a bunch of friends to all
get on at different exits and do it simultaneously. The end goal being
official "pace cars" coordinated by a central command center to alleviate stop
& go traffic and keep everyone cruising at a constant speed. Needless to say,
my mind wanders a lot when I'm stuck in traffic!

~~~
refurb
I've actually done something similar. When in bad traffic i purposely drive so
that i leave a large gap between me and the car ahead of me. I basically drive
so that i have to do minimal accelerating/braking. Likely just a coincidnce,
but it does seem to improve flow.

~~~
covercash
Are you located in/around Philly? If so, I'd be interested in coordinating
something on 476 or 422 one afternoon.

~~~
refurb
Nope! Bay area (which btw, does not have bad traffic relatively speaking; I've
been in traffic jams in the NE and they are way worse, same with LA).

------
aba_sababa
This is awesome. The problem is that no individual agent is incentivized to
drive slower. I wonder if it'd be worth it to hire "stir-the-pot cars" whose
job it is to drive slowly during rush hour and ease jams. Kind of like dietary
fiber for the road.

Hey, doesn't Uber have a whole fleet of cars in cities around the world? It
would be a cool $&@! project for them to be the all-wondrous curers of
traffic.

~~~
rosser
I think the problem is less one of incentive than it is one of awareness. If
more people knew about — and actually _understood_ — anti-traffic, more people
would employ it. I don't know where the inflection point is, but I'd bet you
don't even need all that many people engaging in anti-traffic behavior before
it has an appreciable impact, either.

------
sigil
If you're interested in the physics of it, there's a PDE that explains these
backwards propagating density shockwaves (aka traffic jams).

[http://en.wikipedia.org/wiki/Burgers'_equation](http://en.wikipedia.org/wiki/Burgers'_equation)

------
rallison
If you enjoy this sort of stuff, the book _Traffic: Why We Drive the Way We Do
(and What It Says About Us)_ by Tom Vanderbilt[1] is an enjoyable read. He
covers traffic waves and a lot more.

[1] [http://www.amazon.com/Traffic-Drive-What-Says-
About/dp/03072...](http://www.amazon.com/Traffic-Drive-What-Says-
About/dp/0307277194)

------
WalterBright
> My single tiny car had erased miles and miles of stop-and-go traffic. Just
> one single "lubricant atom" had a profound effect on the turbulent particle
> flow within the "tube".

I did this in the 1970's. It gets rediscovered constantly.

------
notmarkus
The problem with leaving a gap is that, as soon as it's a few car-lengths
long, people in the adjacent lane(s) notice that there's a gap and quickly cut
into your lane to fill it, because it moves them a car-length or two forward.
In order to do this, they have to cut in front of you, speed up quickly, and
brake quickly. And you're left in the same position that you were in before
you made the gap -- plus one extra car.

I try to do this all the time and it's frustrating because it's completely
impossible. As soon as a vacuum exists, drivers rush to fill it.

~~~
ChuckMcM
So its interesting to watch the traffic around when this happens. It actually
smooths out the flow "behind" you because the folks who cut in front eased up
pressure behind them. The tail gater issue is real though so if you're going
to do this it is best to do it in the right lane rather than one of the inner
lanes.

~~~
timthorn
My experience has been that the "slow lane" is usually significantly faster
through a jam, probably because of the number of lorries practicing smooth
driving.

------
tempestn
Can't do this for traffic waves, but it would appear the ideal solution to
merge slowdowns is to have different speed limits before and after the merge.
Regardless of anything else, the flow rate before and after a merge must be
the same. Ideally you want the flow rate after the merge to be approximately
one car every 2.5 seconds, with those cars traveling at the speed limit. (As
opposed to the usual situation where post-merge traffic accelerates from a
near stop, causing large, unnecessary spaces to form.) One way to achieve this
is to have pre-merge traffic leave twice the space, but it's unlikely there
are enough traffic-flow vigilantes out there to achieve that, if such a thing
would even be desirable. Much easier is to keep the same time spacing between
cars, but to have pre-merge traffic travel at half the speed. Traffic
approaches the merge in two lanes, traveling at 50 km/h. The speed limit
increases to 100 km/h, then immediately afterward the traffic merges. Speeding
up from 50 to 100 naturally opens spaces, and traffic merges painlessly. There
is no reason for a slowdown to occur, so no self-perpetuating gridlock.

Of course, the slower speed limit is only useful when the road is filled to
capacity; otherwise it would be inefficient. So for most roads you would want
this limit to vary based on time of day (or even dynamically based on traffic
volume, but obviously that would only be useful/necessary in extreme cases).

------
rheide
This is the prisoner's dilemma. If you slow down and drive smoothly, and
everyone else does too, then everyone benefits greatly. But if you cut in
front of one of the smooth drivers, which you can since he's leaving lots of
space, you benefit personally by gaining a car length while inconveniencing
everyone else in that particular lane. Well, at least until the guy behind you
has smoothed out the difference. Human nature makes smoothing out traffic an
improbable solution.

------
makeramen
This is really interesting. I wonder if the existing California Highway Patrol
practice of swerving around the highway[1] to slow down traffic can be used to
create these "anti-traffic" gaps during rush hour?

[1]
[http://articles.latimes.com/1996-08-12/local/me-33464_1_traf...](http://articles.latimes.com/1996-08-12/local/me-33464_1_traffic-
enforcement)

~~~
lewispb
Near where I live in England we have managed motorways which employ electronic
displays and enforce the speed limit with speed cameras.

[http://en.m.wikipedia.org/wiki/Managed_motorways_in_the_Unit...](http://en.m.wikipedia.org/wiki/Managed_motorways_in_the_United_Kingdom)

------
seanp2k2
Even better solution to traffic: develop real high-speed rail in the US, live
closer to where you work / need to be (stop suburbs / sprawl), ride bikes or
even just motorcycles / mopeds in California where filtering is legal, or
walk.

This has a lot of other nice first-order benefits like real communities,
decreased pollution, less time wasted commuting, and tons of second-order
benefits.

------
pbnjay
Someone at Waze should get on this. Send a small notification to Waze users
that there's a jam ahead, and to slow down by 10mph to help alleviate it! It's
a simple solution and might even work since Waze users are already a
"community" of drivers in the sense that they're looking out for each other
and not necessarily just themselves.

------
adacosta
I usually try to avoid hitting the brake as much as possible in order to
maintain the most uniform speed I can. This is due to a selfish, lazy
motivation, because I don't want to rapidly alternate between gas and brake.

I think there is also a psychological component to seeing bright red brake
lights. I want to say it creates a reactive, and often overly reactive
response. I imagine lifting a foot off the gas pedal often creates sufficient
deceleration without the alarm caused by hitting the brake pedal but many
people don't drive this way. Maybe we should have two shades, or colors, or a
full gradient to indicate level of braking? What if a brake light could
indicate current speed?

------
caw
Interesting blog article.

I've always found it strange that when school is out, traffic is like 30-50%
better. This effect is the best I can think of, because I wouldn't think
there's a lot of people directly impacted by the school schedule. Elementary,
middle and high schools all start and end at different times, and there's
people directly employed by all of those schools, and certainly some parents
who pick up and drop their kids off, but still it doesn't seem like that many
people compared to how much better the traffic gets.

So maybe this article is right, you take a few people off the road and the
merging madness, and everything becomes better.

~~~
codfrantic
I notice the same thing, Even in one week holidays where only the elementary
schools are closed the traffic is much lighter. I expect this because a lot of
working parents take this week off too to be with the kids, probably a 10-15%
drop of traffic means that traffic is a lot easier.

------
platz
I remember some sort of experiment in Colorado in which state police formed a
line of cars at intervals forcing everyone to drive the same speed, and thus
was able to eliminate the daily blockages in that experiment.

------
dirkgently
A related Japanese experiment on the Human factor of traffic jam -
[https://www.youtube.com/watch?v=Suugn-p5C1M](https://www.youtube.com/watch?v=Suugn-p5C1M)

------
frogpelt
The merging solution is oversimplified. Leaving enough space for another car
in front of you sounds easy. But in reality, if 1,000 cars each add 2 car
lengths in front of them you've added 40,000 feet to the length of the slow
down. Yep, 7.5 miles.

If it was feasible, we could also stop at red lights with 3 or 4 car lengths
between each car and when the light turned green everyone could go at the same
time. There isn't space on the road for this type of behavior.

------
mappum
I found the idea that one person can make a huge difference really
interesting, I will have to start experimenting with this myself. All the
roads OP wrote about are where I drive, but the Lynnwood ramp he talked about
recently got expanded.

This also makes me want to make some sort of simple traffic simulator to do
experiments like this, does anyone know if any already exist?

------
mortehu
My heuristic when trying to help get rid of a traffic jam is this:

> Maintain a higher minimum speed (and the same or higher average speed) than
> the car in front of you.

The only reason why traffic jams ever disappear is that people are doing this.
Most of the time I guess the true root cause is that incoming traffic is
dissipating, though.

------
EGreg
I am reminded of this:

[http://www.technologyreview.com/view/425435/in-car-
algorithm...](http://www.technologyreview.com/view/425435/in-car-algorithm-
could-rapidly-dissolve-traffic-jams/)

------
Stark2
On the freeway system in LA, a lot of the jams are caused by slow drivers in
the passing lanes. Most the time, when there's a clump of cars and empty space
ahead of them, it's one or two slow drivers blocking the passing lanes.

------
jdleesmiller
There's a nice simulation of these physics here: [http://www.traffic-
simulation.de](http://www.traffic-simulation.de)

The jams seem pretty robust, unless you turn down the input flow -- a bit like
real life!

------
mooze
There's a whole chapter on traffic jams in the book Critical Mass. From what I
remember, innocuous things like a single driver slowing down can cause massive
jams due to the natural 'physics' of traffic.

------
clarky07
reminds me of an experiment by some college kids in atlanta -
[http://www.youtube.com/watch?v=OoETMCosULQ](http://www.youtube.com/watch?v=OoETMCosULQ)

------
brownbat
Jams spontaneously occur after a certain road density is reached.

The sadistic side of me wishes they'd just close entrances to the highway
whenever it's dangerously full.

------
chrismealy
I saw William Beaty's zen traffic warrior video years ago, and I don't know if
it works, but it sure makes me more relaxed when I'm driving.

------
sly010
Does this mean it's actually possible to improve traffic by introducing extra
tempo setter cars whose only job is to smooth traffic?

------
matiasb
interesting!

~~~
vladoh
This reminds me of an interesting traffic simulation applet, where you can
control things like aggressiveness of the drivers, traffic density etc. and
observe the traffic jam that happens.

[http://www.carbibles.com/trafficmicrosimulation.html](http://www.carbibles.com/trafficmicrosimulation.html)

