There is a secret zoo that runs encaged along the roads.

They are liquid, semi-visible goliaths that rage through the streams and chunks of ordinary traffic, with the effervescent tendrils of mile-long tales whipping behind them like Chinese dragons. Though composed of hundreds of pounds of steel, glass and plastic, they are able to pass through solid objects. They are bound by the laws of the highway, but not by any conventional notion of time or space.

They are Aggregate Traffic Animals: a menagerie of emergent beasts drawn from the interacting behaviours of many individual human beings driving many individual cars with many individual goals, their collective activity giving rise to something with greater presence, power and purpose than the sum of its constituents. They take on a host of different forms, each to serve a different end.

They are real, and they drive among us.

Preamble

In his introduction to The Extended Phenotype (Oxford University Press, 1982) enthusiastic evolutionary biology cheerleader and Commodore-hacking pop-science guru Richard Dawkins invites us to consider the Necker Cube Illusion: a two-dimensional image representing two interlocked three-dimensional blocks in which the foreground and background can seem to flip back and forth as the brain fruitlessly seeks the "true" interpretation of the depicted space. This is Dawkins' starting point for a thought experiment in which he blurs the lines between species, their genes and the environment, calling into question the traditional boundaries drawn through biological systems to identify the relevant level of study. To wit, to wank:

We look at life and begin by seeing a collection of interacting individual organisms. We know that they contain smaller units, and we know that they are, in turn, parts of larger composite units, but we fix our gaze on the whole organisms. Then suddenly the image flips. The individual bodies are still there; they have not moved, but they seem to have gone transparent...

In other words, if you are able to de-emphasise the organism itself you are free to appreciate the idea of beaver ponds as artificial lakes generated by beaver genes, or to see a spider's web as an arrangement of silk drawn by DNA. By extending the lines with which we bound the traditional phenotype, we define new organisms, merging technology and individuals into communities the same way that ancient micro-organisms interacting inside bilipid membranes fell into symbiotic lockstep dances to found the first stable cells.

Organelles, cells, bodies, herds: at which level we discern the animal is purely a matter of focus.

This idea of the emergent animal or "super-organism" is hardly particular to Dawkins: William Morton Wheeler remarked on the idea in his 1911 paper "The Ant Colony as an Organism" in a treatment that is every bit as cogent but with considerably less otaku chic than Kevin Kelly's printed-soundbyte manifesto on hive complexity, Out of Control (Perseus Books, 1994). In the words of Kelly:

There is nothing to be found in a beehive that is not submerged in a bee. And yet you can search a bee forever with cyclotron and fluoroscope, and you will never find a hive.

So too can you examine a driver in a car and know nothing about the greater animal in which they both participate when the circumstances are right. Some of the applicable forces can be seen most clearly in the rarified environment of the professional race course, as explored by David Ronfeldt, a senior social scientist at RAND, in his 2002 paper Social Science at 190 MPH on NASCAR's Biggest Superspeedways, where fleeting moments of co-operation between rivals are necessary in order to win. Ronfeldt focuses in particular on the phenomenon of draft line formation, which is similar to the way flocking birds can share aerodynamic advantage. Like iron filings in a magnetic field, the large-scale distribution of opportunistically partnering cars are drawn into predictable macro-scale patterns across the speedway:

Once the racers sort themselves out - after ten to twenty laps - it is common to see a single draft line of four to seven cars running in front, pursued a hundred or so yards back by a second line of cars, all another hundred or so yards ahead of a large pack of cars that may still be running in parallel lines but are doing more dicing than drafting...Cars that run alone, often stuck dangerously between two draft lines, will appear to drift irrevocably backward.

Freed of the bonds of racing's formalism, the Aggregate Traffic Animals are born, rooted in transient symbioses between individual patches of drivers that will crystalise into the organs of the beast. But the circumstances have to be just right for one to emerge. The unholy Hieronymus Bosch-style concert of homicidal applied-shadenfreude that may characterise your urban, intra-urban or sub-urban driving experience is not ripe ground for ATA growth: too frothy.

The sociological and scatological dances of the megalopolis rushhour, too, are beyond the scope of this article, and are at any rate most likely best explored with deep computer simulations using high-tech cellular automata tools with average driver profiles linked to real-world statistics of roadway usage coupled with an army of ten thousand angry ax-wielding orcs battling an equal number of obedient clonetroopers.

Rather, this field is perfect fodder for the amateur ethologist, observing phenomena with a keen eye, an open mind and a sharp pencil. And while much has been written about manipulating traffic waves, the dynamics of traffic jams and phase-transitions in traffic density, very little time has been devoted to the observation and cataloguing of persistent multi-car zoomorphia.

Early Observations

The author first became aware of the existence of ATAs while making his way through the hinterland of Canada on a long, mid-winter solo drive in a decrepit Dodge Charger with no functioning radio. Due to his dangerous penchant for immersive daydreaming in the absence of external stimuli, he began to parasite his driving decisions by locking in behind another car with comparable speed ambitions. By reserving a sliver of awareness for tracking the red brake lights of the "lead" car for changes in speed or direction, the author was able to comfortably enjoy his trance while a hefty burden of road awareness was outsourced to the other driver, causing the front car to function as a sort of early warning mechanism for changing conditions (including the Mounties' speed-traps).

The notion resurfaced while the author was wrestling a dented Volkswagen Rabbit rental down a twisting, pot-holed two-lane jungle highway through the Mexican state of Quintana Roo. As the journey began he found himself hedged inside a short parade of other tourists, all driving their rental cars out of the airport at around the same time at a hesitant pace, breaking frequently to process the unfamiliar leafy darkness ahead. Fearing injury, the author laterally-leapfrogged the indecisive parade and drove on into the murk alone. Remembering his success in the far north, he latched onto the back of a local vehicle (a home-modded convertible Beetle carrying ten people, standing room only), using its varying speed as an indicator of road conditions. Unexpectedly, this move was noticed by several of the other tourists, who began to fight to separate themselves from the melee and join the newer, more surefooted pack that was rapidly pulling ahead...

By the time the author had reached his exit the impromptu fleet of vehicles had become a persistent, homeostatic phenomenon. The fleet had quickly learned to manipulate the spacing between its components in order to remain permeable to faster moving local traffic while defending its integrity against more disruptive external vehicles. Pulses of communication signifying when the passing lane was clear rippled down the chain through a conscientious leaning into the gravel shoulder, assisting in the process of expectorating invaders. Several of the original tourist vehicles ended up being swapped out for other vehicles without rocking the boat. Later on, even the leader was swapped out for another experienced local car.

It was a fetching game, contributing to the welfare of all of its players in an interesting way, but it was not a true ATA. It was too conscious a contrivance to be anything more than a delightful spontaneous social event.

You see, a distributed animal with human components can be very sensitive to perturbations from within. It is only when the conflicting threads of goals, reasoning and competition between individual human minds are quietened into the background noise that the soil can truly be ripe to raise a complex beast. When drivers can fall into a semi-hypnotic state and their herd instincts take over, the seeds are laid for something greater.

Habitat

While there are thousands of traffic animal breeding grounds along the paved networks of the world, only one driving region has been extensively explored at this time, largely due to budgetary considerations.

The TransCanada Highway is a nearly ideal environment for the production of large-scale ATA phenomena, due in great part to the simplicity of its shape: all cars are moving either westbound or eastbound, streamlining the goals of the drivers in much the same way as the shape of the Daytona superspeedway encourages drafting partnerships (see above). Also, because there are long stretches through lonely wilderness and semi-tundra, nascent traffic animals have a long period in which to mature before coming against obstacles like influxes of new cars or navigating around towns; and because the highway wends its way directly through most of Canada's major cities, it provides a handy litmus test for the homeostatic integrity of a given specimen simply by observing whether or not it makes it through to the other side of the urban area intact.

While daytime ATA formation is not rare, it is under the cover of darkness that development can proceed in a comparatively unfettered fashion. This is due in large part to the more abstract, disconnected experience of interacting with other vehicles merely as points of coloured light. Familiar prejudices and stereotypes -- potential sources of destructive competition -- are smoothed out by the shadows. At least on the basis of visual impressions, a Volvo and a Camaro can enter a system as peers.

Diminished visibility resulting from mild to moderate weather conditions can have a similar equalising effect, but when conditions become too severe drivers tend to clump into packs for safety, leading to pseudo-ATA fleets that are all too conscious social events (as in the Quintana Roo experience).

Show me an autumn stretch of prairie transcontinental highway at twilight, and I will show you the secret zoo of the road.

Typical Morphologies

The most basic form of multi-car life is the Asipetal Caterpillar, also known as a worm. Worms begin when a stable solo vehicle spawns a linear, single-lane chain of vehicles composed of loose monomers joining at the rear (a closely related, but dysfunctional, construct known as an Acropetal Caterpillar grows by adding vehicles to the front of the chain, generally leading to destructive diffusion or autolysis). Short, lithe worms are the fundamental building blocks of healthy ATA tissue. Perverse, long-form worms are the seeds of congestion and death.

The second atomic element of ATA tissue stands in stark contrast to the worm, for it is a fleeting thing, and when it takes concrete form at all it is often manifested as a single car. The Apparent Coxswain is a vehicle that appears, to the conscious or semi-conscious mind of one or more drivers, to be a leader of the worm. When the Apparent Coxswain changes lanes, there is a higher probability that a majority of the worm will follow suit than if the change were initiated by a less trusted vehicle. In many cases each car in a worm perceives the car immediately ahead of it to be the Apparent Coxswain, leading to domino-effect lane-transitions; such formations have high homeostatic integrity because of the worm's ability to "find a new head" should one Apparent Coxswain be lost to the currents. (Please note: the Apparent Coxswain should not be confused with the Virtual Coxswain or the Napoleonic Coxswain, discussed below.)

Formations that achieve such integration become Cholingers: Asipetal Caterpillars with tightly-integrated internal feedback systems of Apparent Coxswains, capable of transmitting information from tip to tail with high fidelity. Cholingers can slither to avoid torn tyres on the road, twitch around slow-moving vehicles, and even slip through packs of alien worms, wild axenes and other traffic froth to arrive on the other side intact.

Of course, not all Cholingers slip through the strangers: sometimes they interact.

Every Cholinger is either benthic or pelagic. Benthic Cholingers travel at a similar rate to the currents of the road, while Pelagic Cholingers travel at a dissimilar rate when compared to other traffic (typically a faster rate). It is possible, however, for a benthic line to be picked up and carried along by a pelagic cousin, leading to a coupled form. This is the first real Aggregate Traffic Animal we will meet tonight: a bilaterally asymmetrical diageotrope known as the Epiphysian Cyclosalp.

Within the body of the Cyclosalp the individual Cholingers are transmuted into a pair of Librigenates -- stretchy, free-flowing tissue that is bounded in space by the relationship with its partner, the accelerating pelagic lobe sliding forward and the steady benthic lobe catching up in a slow-motion slingshot, compressing and expanding between the loose, senseless clumps of other cars. This accordion-like effect might initially seem to be a force tearing the animal apart, rending pelagic from benthic -- and this is indeed what might happen in too rarified an atmosphere -- but when presented with obstacles of any kind, the Librigenates that comprise the Cyclosalp fall back on their Cholinger heritage of local integrity, crystallising en masse to navigate the hazard.

Unfettered, the Epiphysian Cyclosalp is like half a butterfly, its riparian body gilded by a slowly flapping wing of accelerating, gliding Librigenates ebbing and flowing in a stately round. Its insides whorl as partners switch places, benthic turning briefly pelagic, pacer cars joining a rippling pulse of local inertia forward, headlights cross-sweeping.

It is beyond the scope of this article to detail the myriad circumstances that provide seed for the profitable entanglement of multiple Cyclosalpic streams. So diverse are the possibilities that we could fill a Biblical tome without scratching the surface, without revealing the common thread of simplicity upon which the complexity hinges. Suffice to say the larger clade includes such varied forms as the whiplashing Epinastic Tricyclosalp, the many-fingered Dicyclosalp Fimbriatum, and the diaphanous, fleeting wonder of the mile-long Merosporangic Super-Cyclosalp...

Of course, not all Asipetal Caterpillars grow up to become stately Cholingers; instead, they lock into Lego-like bricks of uniform properties called Pycnoblastoids. While short-lived Apiculate Pycnoblastoids (in which the Apparent Coxswain is always the most forward car) are more common, it is the more flexible Laxiflorous Pycnoblastoid (in which the Apparent Coxswain is any car except that most forward) that lives a more fruitful life.

For instance, consider the case of a typical composite entity like a Tripycnoblastic Oomycotum, in which independent pycnoblasts jockey for position internally directly or by proxy through one or more Napoleonic Coxswains (that is, drivers who suffer from the delusion that they are single-handedly responsible for steering/leading their local sub-structure). The domino-line behaviour of an Apiculate Pycnoblastoid makes it too brittle to survive the stresses of being permeated by a competing pycnoblast, whereas the comparatively elastic structure of the Laxifloroid -- imparted due to the inherent time delay involved in co-ordinating with a mid-fleet Apparent Coxswain -- retains a perfect balance of rigidity and looseness, riding a line between orchestration and dissolution that makes composite forms like Oomycota possible.

Pycnoblastic tissue is unusual in that it makes use of some level of awareness on the part of the driver that they are participating in a formation (though drivers are only likely to be aware of the local level of structure). When this awareness reaches a certain level the composite entity is usually destroyed by internal stresses, but occasionally a dissolving multi-pycnoblast will emit a stream of highly energised vehicles -- the Apheresoid Lirellate, a concentrated apiculatoid pycnoblast flung free from the miasma of death to rocket away, using for a coxswain the abandoned carcass itself.

...These are but the fringes of the zoo, the tip of the iceberg.

We have not even touched on the sensitive antennae of the Stipitate Phototaxites fringed with Virtual Coxswains, pseudo-lead cars ready to be sacrificed to trip any trap, the chaotic wrath of the Biflagellate Ableptic Figmo and the fate of the cystidial flotsam locked within them; the weird rhythms of the Cacospysic Super-Barbicanoids and their elaborate dance of shifting coxswains, the majesty of the motorcycle-based Raging Fallaxoid; the menagerie of endless cancers that can grow from unexpectorated papillic granulomae, from cataracts of geriatric nektons, or from service-stations with badly planned driveways.

Further Study

The study of a new order of life is not without its risks, both professional (in terms of reputation) and practical (in terms of being maimed by mis-navigated vehicles). The amateur automotive ethologist must not only have keen skills of observation, but also the fortitude to persevere despite the slings and arrows of dubious dissenters. Like Leeuwenhoek's controversial animalcules and Pasteur's superstition-defying microbes, there will always exist a certain testudinal resistance to new ideas among older quarters. There will be those who doubt the very existence of aggregate vehicular life, or who insist that the zoo of the road dwells in metaphor alone.

The opinions of such sceptics could be changed by a single night spent on a grassy hill overlooking a well-travelled country highway, watching the streams of red and silver lights merge and split, compress and attenuate, roil and interact, fatten and reproduce...

Watch the roads, and see the zoo for yourself. There is no denying its patterns of insectile purpose, its myriad variations in anatomy and configuration, or the orchestrated madness of the low-cost petroleum feeding frenzy. Your own mind, honed by thousands of generations of natural selection to recognise life from non-life, will tell you it is true; the disciplines of careful observation and meticulous classification will tell you how, and why.

Open your eyes, and witness an untapped world.