
Ants Are Practically Immune to Traffic Jams - laktak
https://www.sciencealert.com/ant-roads-are-practically-immune-to-traffic-jams-even-when-it-gets-crowded
======
mrfredward
A major oversight here is rate of acceleration. Every organism and vehicle on
earth has the same gravity and similar coefficients of friction to work with,
so rates of acceleration have roughly the same cap, but the speeds change by
orders of magnitude.

So an ant can go from full speed, to stopped, to full speed in a fraction of a
second. A car on the highway will take several seconds to stop, and much
longer to smoothly accelerate, leading to standing wave type effects on
highways. This is much less likely with people walking, and even less likely
with ants.

The dynamics of cars on the highway is governed by the difficulty of changing
speed and direction. For ants, this constraint is negligible. So these things
don't really compare.

~~~
jerf
I also really loved the throwaway about ants not caring about collision.

I can "solve" a lot of traffic problems too, if nobody involved is worried
about collisions.

~~~
Johnny555
I think that's part of the promise of self-driving cars -- they'll ostensibly
be safer, so can drive closer together, and can cooperate at intersections to
increase throughput, no one needs to stop, just adjust speed to allow a gap.

Though based on my car's adaptive cruise control ability, we've got a long way
to go before we can have cars that drive within a few feet of each other at
highway speeds, and even longer before we could have intersections without
signals (or stops).

~~~
alpaca128
I don't know if this promise will ever be real in that extent. Even if you
assume perfect drivers(automatic or not) with instant reaction speed there can
be situations where a road can become impassable quickly due to external
influences, and this alone makes short distances between cars unsafe.

All it takes is one rock dropping onto the road heavy enough to immediately
stop a car in its tracks, and what would follow would be a series of
collisions affecting a large number of cars.

Then you need to leave gaps for new arrivals from a different road, and in the
end I don't think the efficiency would be that much higher.

~~~
waste_monk
Presumably autonamous cars would maintain proper separation - I try to
maintain a three to five second gap between myself and the next card, but
drivers in my area tend to be quite aggresive and will force their way into
the gap - I have nearly been hit or run off the road multiple times.

I think the benefits are more that the car strictly obeys road rules, as
opposed to humans being unaware, ignoring, or straight up willfully breaking
(e.g. speeding) the rules.

<rant>

On my path to and from work there is a "trouble nexus" \- you have a few main
roads intersecting, a relatively short stretch of road with a couple of
entrance/exits towards a public transit hub (trains, buses, and a large
carpark converging - so there's a lot of road traffic), then a bridge, then
another major intersection and exits onto a highway.

People are always slowing down to create a gap in the traffic flow and let
vehicles from the transit hub onto the road leading up to the bridge, in an
effort to be kind towards other drivers, but this has disastrous effects on
the traffic behind it - interrupting the traffic flow of the major roads.

If people did not make space for vehicles from the side roads, the main flow
of traffic would pass fairly quickly and then the sideroad traffic would be
able to get on noramlly.

</rant>

The point I am trying to make is that autonamous cars would let traffic
planners adjust e.g. road speeds, traffic light timings, etc. closer to a
global optimum without having to account for human selfishness.

------
imgabe
> Whereas, when a trail is overcrowded, the ants restrained themselves and
> avoided joining until things thinned out.

This sounds a lot like how traffic waves [1] occur. When there's a traffic jam
ahead, you can often help clear it out just by slowing down to the average
speed it's moving. Going a steady 10mph is much better than going 30mph for
1/3 of the time and then being stopped for 2/3 of the time. If everyone can
start going smoothly at 10mph it will eventually speed up.

Traffic jams occur because cars are arriving at some point on the road faster
than they can leave that point. If the cars coming towards it just _slow down_
to allow the cars there time to leave, the jam will clear.

[1] [http://trafficwaves.org/](http://trafficwaves.org/)

~~~
CogitoCogito
I use this method to an extent, but the unfortunate result often becomes
people zipping in in front of you when you inevitably have a bit of extra
space compared to those around you. This seems to leave you with two problems
which are hard to solve simultaneously. The first is the one you mention where
you want to keep a mostly constant speed compared to the whole group. The
second is the effective need to locally keep up with the cars around you.
Solving both problems simultaneously seems essentially impossible. I guess
removing self-interest is the only real way (which appears to be what the ants
do).

~~~
orthecreedence
The slow-n-steady method really only works with a critical mass of
participation. Unfortunately most people either don't know that it helps or
don't care and are happy to just keep stomping the gas and breaks repeatedly.

~~~
lotsofpulp
Slow and steady only works up to a certain vehicle density. Once that has been
exceeded, slow and steady simply serves to cause congestion further back in
the road than necessary.

There is no way around stop and go traffic once the maximum capacity of
flowing cars has been exceeded. After this, leaving extra space is just waste,
which is why in more densely populated areas, people "cut" into the space in
front, because the only optimization left is to use as much road as possible.

~~~
mixmastamyk
There are other benefits, enjoyment and reducing wear and tear. Increasing
delay by a few % in a huge jam is not material.

~~~
lotsofpulp
If everyone did it, it would be material. But everywhere I've seen, other
people usually slip into whatever space there is. Which technically does
maximize the rate of vehicles passing through a point in the road, as you can
take advantage of the various rates of acceleration.

Whether or not the time saved is worth the wear and tear, environmental
damage, increased risk of collision, I can't say. I'd say probably not, but
it's going to happen anyway.

~~~
mixmastamyk
Not really, as mentioned in a sibling thread. If you’re in a big hurry, simply
leave two minutes earlier you’ll be ahead of all the folks you’re worried
about.

There is an efficiency gained through having space to change lanes as well,
which is ine cause of the slowdown.

------
OscarCunningham
Looking at that video, a lot of the ants were walking into each other. Maybe
their advantage is just that collisions have low cost so they can afford to
use strategies that even among humans on foot would lead to a painful crash.

~~~
z3phyr
They walk over each other too. We can't do that without causing minor or major
injuries

~~~
quakeguy
Because ants are small... And lightweight, I can’t remember right now the term
for volume vs mass when compared, but you can throw an ant from the Empire
State Building, and it will land like dropped from 2 inch height.

~~~
scott_s
Taken from the Wikipedia page on terminal velocity, and quoted from the
biologist J. B. S. Haldane:

 _" To the mouse and any smaller animal [gravity] presents practically no
dangers. You can drop a mouse down a thousand-yard mine shaft; and, on
arriving at the bottom, it gets a slight shock and walks away. A rat is
killed, a man is broken, a horse splashes. For the resistance presented to
movement by the air is proportional to the surface of the moving object."_

~~~
quakeguy
Thx, that was the quote i was looking for.

------
thisisbrians
I live and work in downtown Austin. I frequently walk (about a mile each way)
to/from my office, so I spend a lot of time interacting with and observing
traffic patterns in a very automobile-congested area. One of the biggest
issues I've witnessed is how frequently drivers will proceed into an
intersection even though there isn't enough space ahead of them to clear the
intersection. Then, the signal changes, and they are left blocking one or more
travel lanes perpendicular to their vehicle, thereby spoiling the precious
open road for the unfortunate motorists who are left to deal with their
selfishness or inattentiveness.

I see this happen almost daily, so I can only imagine how often it actually
occurs when I'm not around to witness it. I wonder how much this slows the
whole system down just so that a few folks can hopefully get where they're
going one traffic light-cycle sooner. I'd be mortified to be sitting in one of
these cars getting honked and glared at for my complete and utter lack of
consideration towards others, but I guess selfishness is a powerful enough
force to keep people driving like assholes regardless.

~~~
steveklabnik
I also live and work in downtown Austin, and see this all the time too.
It's... less than ideal, for sure. At least when people block the pedestrian
crossing, (which is also something I encounter daily) it just makes it
awkward, rather than gumming up traffic too.

~~~
thisisbrians
Rad, didn't know you'd moved to Austin. We are using Rust for a couple
projects at my startup now: bractlet.com

~~~
steveklabnik
Oh cool!

If you ever want to grab a coffee or something, let me know :) we’re also
doing rust lunches every other week downtown.

------
Steltek
Because they're not ant roads, they're ant sidewalks? How can someone have
such a blind spot of basic facts. Check out any street fair or large public
outdoor event. People are going everywhere, despite a high density of people.
It works because people are not driving.

~~~
zaphod420
It's kind of amazing how selfish people become once they are driving a car. If
people drove in a way that focused on keeping traffic flowing it would work,
but cars are just big ego bubbles.

~~~
timerol
This is commonly believed but untrue. A certain volume of vehicles will
drastically slow a road, regardless of how well people drive. Unless by "drove
in a way that focused on keeping traffic flowing" you mean "wait in the on-
ramp merge lane until rush hour ends".

A corollary of the above fact is that autonomous cars won't save us. They
might make traffic better by about 20%, but induced demand allows us to
predict that speeds during rush hour won't actually get better.
[https://en.wikipedia.org/wiki/Induced_demand](https://en.wikipedia.org/wiki/Induced_demand)

~~~
mkagenius
Cars are truly one of the mistakes the human civilization latched on to. With
fossil fuels going out of fashion, cars need to go too. We do not need car not
even battery powered car. Maybe one car per 100 people is what should be okay
for emergency purposes.

~~~
jimmaswell
Thankfully this extremist position is going to remain an unimportant minority
for the rest of my lifetime.

~~~
lazyjones
That kind of extremist minorities are far too often found working in
journalism, so-called science (rather academic activism), politics etc. ... So
I'm not too optimistic about these trends.

------
sriram_iyengar
Basis of the article is questionable. Humans slow down on traffic to avoid
accidents. Ants don’t have that constraint. Neither will ants cause a stampede
and can suffocate to death.

~~~
spsful
The article frustrated me because it contradicts itself several times.

>When it's moderately busy, for instance, the authors found the ants actually
speed up, accelerating until a maximum flow or capacity is reached.

Then from the next paragraph:

>Plus, at high density times like this, the ants were found to change their
behaviour and slow down to avoid more time-wasting collisions.

Did I miss something here or does this legitimately make no sense?

~~~
PhasmaFelis
At low density, ants move at a speed that maximizes efficiency. At medium
density, they move a bit more briskly, sacrificing some energy to keep from
blocking traffic. At high density, they move more deliberately, avoiding
situations like we see on highways where a single vehicle advances rapidly but
slows down many others as they brake to avoid it and cause a traffic wave.

------
animal531
I would consider the Ant Death Spiral to be a pretty bad traffic jam:

[https://www.youtube.com/watch?v=N0HoqjxfvJ4](https://www.youtube.com/watch?v=N0HoqjxfvJ4)

~~~
z3phyr
That's not a traffic jam. It's basically mass suicide after getting lost

~~~
jakobegger
According to the description, they didn't die, they somehow dispersed again
after 30 minutes.

~~~
z3phyr
They were probably "found" by another "foraging party" of their own colony.
Even if one of them regains active pheromone trail, all of them can safely
return.

------
DeusExMachina
> In fact, compared to humans, these ants could load up the bridge with twice
> the capacity without slowing down.

Then, on the next paragraph:

> And they do this through self-imposed speed regulation. When it's moderately
> busy, for instance, the authors found the ants actually speed up,
> accelerating until a maximum flow or capacity is reached.

Doesn't this mean that they do slow down?

~~~
SimplyUnknown
I'm speculating that "slow down" in your first quote means "the flow doesn't
plummet towards zero when it's busy" and in the second quote it means "reduce
their average velocity". So in that sense they don't slow down (i.e. the
colony doesn't grind to a halt) because they slow down (i.e. literally slowing
down)

Again, I'm speculating about the meaning but if I'm right then it's a poor
choice of words from the author.

------
ossworkerrights
"Traffic jams are ubiquitous in human society where individuals are pursuing
their own personal objective,"

Perhaps humans don't have the option of walking / driving through wherever
they please, and instead they have to use fixed roads / sidewalk? I'm pretty
sure if we had the option of driving on dirt we would easily avoid traffic
jams, as we'd just drive wherever we want.

~~~
ellius
Valid point, but the article does mention that ants are at least somewhat
constrained to the narrow paths laid out by their colony's pheromones.

------
vezycash
Ants can create new paths on demand. Ants on a trail typically have the same
destination. Ants aren't going to park on the already tiny trail unlike
humans. Bumps, potholes slow down cars and limit ability to increase speed
unlike ants.

We'll be finally able to traffic jam free when flying cars become the norm.

~~~
donmatito
That's not what the article is saying. They have tested ant flow on narrow
bridges where additional lanes aren't possible.

From the article:

"they do this through self-imposed speed regulation. When it's moderately
busy, for instance, the authors found the ants actually speed up, accelerating
until a maximum flow or capacity is reached.

Whereas, when a trail is overcrowded, the ants restrained themselves and
avoided joining until things thinned out. Plus, at high density times like
this, the ants were found to change their behaviour and slow down to avoid
more time-wasting collisions."

We'll be finally able to traffic jam free when autopilot will make us slow
appropriately in high density conditions, avoiding accordion-like
brake/accelerate/brake cycles

~~~
CodesInChaos
Congestion dependent speed limits have been in use for a long time on German
highways.

~~~
Spare_account
The principle is sound, but the ants actually obey the rules whereas (in the
UK at least) a small contingent of human drivers will ignore the limits,
speeding up and slowing down between enforcement cameras. This concertina
effect from just a small number of drivers is enough to slow the entire flow
of traffic.

~~~
lotsofpulp
It would have happened anyway after a certain density of vehicles is exceeded,
since each car and truck had different accel/decel rates. Especially if there
is an incline anywhere.

------
lazyjones
Perhaps our traffic jams are due to too many rules? Classic video that
demonstrates an alternative way of doing things:
[https://www.youtube.com/watch?v=UEIn8GJIg0E](https://www.youtube.com/watch?v=UEIn8GJIg0E)

~~~
johnisgood
You might want to read about Hans Monderman.

> Monderman's work _demonstrated that city and village streets become safer
> when they are stripped of traffic controls_ so that drivers must take cues
> from observing people rather than signs. Though it sounds chaotic, the
> results of Shared Space have shown to be just the opposite: traffic moves
> slower and the rate of major accidents declines drastically.

> His design approach is the concept of "shared space", an urban design
> approach that seeks to minimise demarcations between vehicle traffic and
> pedestrians, often by removing features such as kerbs, road surface
> markings, traffic signs, and regulations. Monderman found that the traffic
> efficiency and safety improved when the street and surrounding public space
> was redesigned to encourage each person to negotiate their movement directly
> with others.

[https://www.pps.org/article/hans-monderman](https://www.pps.org/article/hans-
monderman)

[https://www.pps.org/article/shared-space](https://www.pps.org/article/shared-
space)

[https://www.maharam.com/stories/rawsthorn_hans-mondermans-
na...](https://www.maharam.com/stories/rawsthorn_hans-mondermans-naked-
streets)

For the record:

> First implemented in his native Netherlands, Monderman’s designs have since
> spread throughout Europe, South Africa, Australia, Japan, and Brazil, and
> Canada. They are also making an appearance in often car-dominated U.S.
> cities such as Pittsburgh, Seattle, Portland, San Francisco, and Chicago.

> "It's a moving away from regulated, legislated traffic toward space which,
> by the way it's designed and configured, makes it clear what sort of
> behavior is anticipated," said Ben Hamilton-Baillie, an English urban
> designer who coined the phrase Shared Space after trying out Monderman's
> controversial ideas in his hometown of Bristol. Hamilton-Baillie now
> promotes Shared Space projects in Germany, Belgium, and Denmark as part of
> an ongoing project of the European Union.

~~~
lazyjones
This line of thought has become very popular among city planners here in
Austria, but I've seen it implemented in 2 different ways:

\- in Vienna, they give priority to pedestrians in such shared zones, cars
have to go very slowly and often struggle with large numbers of people in
areas frequented by tourists. There is also a lot of confusion around the
question where cars are actually allowed to go and when

\- in some tourist areas in Italy, where lower traffic roads have no sidewalks
and cars go 30 Km/h, pedestrians walk on the edge of the street. This seems
just as safe and less frustrating for drivers.

------
YesThatTom2
My summary of this article: Ants knew TCP flow-control long before Van
Jacobson.

------
k__
If there are hundreds of ants all carrying food home it's not important that
one individual comes home quick.

If I want to get home I don't have much to gain from 10 other people coming
home first.

------
sigmonsays
I think this article implies we operate like an ant colony with a single goal.
I may be mistaken but we humans dont't have a single goal so our priorities
are different.

------
ensiferum
What has always puzzled me is that how is it possible that for example in the
army a unit of thousand men can move as a single unit. Yet 5 cars stopped at
the traffic lights can't do this but exhibit a latency accumulating between
every single vehicle. If everyone just started moving when the light turns
everyone could take off at the same time!

~~~
Xelbair
It is a matter of trust.

In army you trust others to move with you.

In car, you know that others won't move anyway so you wait and react to their
behaviour.

Army also moves in cohesive manner - unit is going towards known place.

Car drivers do not know where others want to drive.

Even the purpose of turn signals evade most drivers - they exist so you can
signal your intention BEFORE manoeuvrer - most drivers turn them just before
they need to, or even during the manoeuvrer.

~~~
ensiferum
Yes it was a rethoric question but anyway you said it and there's basically
the answer to the question posed by the scientist. Trust and communication.

In the army some chief gives the instructions. Everyone obeys the instructions
(regardless of whether you trust or don't trust your adjacent soldiers to move
as well).

Seems the problem really is just the lack of co-operation and individualism
that produces a negative externality for the society as a whole.

------
Kaiyou
Watching someone improve traffic of game cities on Youtube I realized that
traffic jams have more to do with how streets are laid out than with the
behavior of drivers. If a city or more broadly speaking the street network was
properly designed traffic jams would only happen in case of accidents or other
unforeseeable traffic loads.

~~~
donkeyd
You're working on the assumption that game traffic is a perfect representation
of actual traffic. In reality, that's not the case though. In games, traffic
on a straight road behaves perfectly. In real life, people cut others off,
forget to check their blind spots, play on their phones, etc.

This type of behavior often causes the 'out of nowhere' traffic jams. Someone
brakes excessively because of one of the reasons above and people behind them
brake even harder. Eventually some people will come to a stop and this will
accordion for a while.

You can play with this here: [https://traffic-simulation.de/](https://traffic-
simulation.de/)

Especially try just disturbing an otherwise nice traffic flow.

~~~
Kaiyou
No, not in that game. People would cut into each others line all the time and
generally behave stupidly. Also, if you have a traffic line where the behavior
of the car in the front affects the cars behind it you already have bad
traffic, which wouldn't happen with properly designed roads.

------
tempsy
Actually really interesting to think about how self driving cars would be
impacted. In a world where 100% of cars are self-driving, but algorithms are
manufacturer-specific, how much more efficient would driving really be? It
would seem like if all cars were operated by the same algorithm then you'd be
able to build something that was more "ant colony" like that would similarly
improve driving efficiency?

~~~
mikepurvis
Even without higher-level coordination, independent autonomous agents on the
road could still do a lot better than human drivers in at least two ways: a)
the jam-busting behaviour described elsewhere on this thread could be built
in, avoiding the counterproductive and unnecessary stop-and-go pattern that
most human drivers seem to fall into, and b) even when traffic unavoidably
comes to a standstill, a self-driving car could have near-instant reaction
time on stopping and starting, meaning that the wave propagation would be much
faster.

This second point is basically saying that if there's a pileup, yes the whole
roadway will stop while it's cleared, but the moment a lane opens up,
autonomous cars will be able to more efficiently and immediately use it to get
the whole jam moving forward.

------
pks016
I used to study ants;Diacamma sp. in India (not the pheromone laying one).
These ants transport individuals through a method called tandem running.

There is also traffic-jam in this species if we narrow the path. Here, also
there is no change in dynamics in the way these ants relocate even when there
is traffic jam (to be published). Interesting to see similar methods adopted
by ants even though the transport method is different.

------
alikim
I feel like a significant portion of human traffic jams are caused by
bottlenecks but as far as I can tell this was not addressed in the study.
Would be interested to see how much more efficient ants are in the case where
the width of the path is variable.

------
Jollyton
Nice and well thought out write up about the ant. Ants are always busy and
preoccupied fulfilling one task or the other. Despite this, there is great
team work and selflessness among the ants, which humanity can learn from and
have a better society.

~~~
JoeAltmaier
Well, anthropomorphism aside, ants kill and eat their peers if they detect
damage or aberrant behavior. They behave as they do, because it is beneficial
to the queen, whose future is the only one that matters.

------
carc1n0gen
I read ant as aunt and was very confused, then realized what happened once
opening the link.

------
CryptoPunk
Because ants are genetically adapted to act selflessly, given they are a
colony.

Humans need externally imposed incentives to act cooperatively, which is where
government and private property comes in.

~~~
misterdoubt
Do we, though?

------
1xdeveloper
I wonder what the effect would be if they measured ants from different
colonies on the same trail?

~~~
dave_b
I imagine the breakout of total war would cause moderate to severe traffic
congestion.

------
fouc
Motorbikes are practically immune to traffic jams, especially if they drive on
the sidewalk.

~~~
jdnenej
Basically everything that is not a car is immune to traffic jams outside of
extraordinary situations like events with narrow exits.

------
ptah
it makes sense to up the speed limit during rush hour instead of the typical
case for humans where we reduce it

------
idlewords
This is because they don't drive.

