On the 15th of September, 2011, near Sao Paulo in Brazil one of the largest ever
traffic accidents in history took place. In heavy fog several vehicles collided,
beginning a chain reaction that ultimately consumed around 300 cars and trucks. The incident
left one person dead and many more injured. While notable for its sheer scale, this pile up is just
one of many such multi-vehicle collisions, many of which have at their route the same basic cause.
While the accident in Brazil was the largest in terms of the number of vehicles involved
it was by no means the deadliest pileup ever to take place.
A collision which occurred on the 29th of November, 1990, on the other hand had a
death toll of 17 persons, despite involving just 104 vehicles. The main cause was a dust storm
which descended on the I-5 north of Coalinga, California, reducing visibility to near-zero
and causing a chain reaction sequence of collisions on both the north- and
southbound carriageways. More than 100 vehicles smashed into five distinct masses of wreckage.
Some drivers were lucky. On the periphery of a crash site they suffered nothing more
than a fender bender, and were able to jump from their vehicles and escape the roadway.
Others, caught up in the middle of the mass, were impacted from all sides, hit over and over again
until escape from their vehicle was impossible.
The main cause of death, however, was not impact. Even in 1990, cars were built to offer as much
impact protection as possible for their occupants, and so most victims survived the initial crash.
It was the fire which burned through the wreckage afterwards that resulted in such a high death
toll, with many vehicles burned down to their bare frames and two victims burned beyond recognition.
The dust storm remained in place during the rescue operation. As fire and ambulance personnel tried
to make their way out to the crash site they were involved in minor collisions of their own.
With so many people injured in the incident rescuers were forced to requisition buses
to transport them all to hospital. Similarly a multi-car pileup in Germany
which took place on the 8th of April, 2011, claimed eight lives, mainly due to a fire
which followed the initial crash. The incident took place on the Autobahn 19 near Rostock
where a freak sandstorm reduced visibility to zero with almost no warning for drivers.
The sandstorm was later blamed on drought conditions which had existed for the last
few weeks, combined with recently-plowed fields adjacent to the road and extremely high winds. For
everyone involved in the crash it was a weather condition they had never encountered before.
Survivors described a "black wall" of sand that enveloped them without warning,
and a road surface made unexpectedly slick by huge amounts of sand and grit.
A truck carrying hazardous materials was involved in the crash and its cargo ignited,
creating a fire which burned 20 vehicles. Again the inability to see complicated everything,
preventing rescue helicopters from landing and making it difficult for rescuers to communicate
or to locate those still trapped in their vehicles. This inability to see what is going
on around them is, for many survivors, one of the most terrifying aspects of these accidents.
Many describe the experience of sitting in their vehicles hearing impact after impact nearby,
unable to see far enough to determine if they are about to be hit again
or if it is safe to try and escape their vehicle and run to the side of the road.
Despite the destruction of multi-vehicle collisions
high death counts are rare. Most crashes of this kind result in a massive number of injuries
but relatively few deaths. Where there is no fire, collisions involving hundreds of vehicles may only
result in a relatively small number of deaths. Many people experience a very lucky escape.
This was the case during a pileup which took place on the 5th of September, 2013, in the UK.
In this incident more than 130 vehicles collided within the space of just a few minutes.
One very fortunate driver, a man named Martin Stammers, was unable to stop in time to avoid
the pile up altogether, but managed to steer his vehicle through a small gap between the wreckage
and the central reservation. When he came to a stop all he could hear for almost 10 minutes
was the continual smash and crash of cars on the road behind him impacting the wreckage. Risking
their lives, Stammers and his son exited their vehicle, skirted the wreckage and
ran back up the central reservation to warn approaching drivers of the crash.
Again, fog was the cause. The area where the crash took place had very poor visibility due to
thick fog and yet many drivers reportedly entered the fog without switching on lights and without
significantly reducing their speed. Some witnesses reported being passed by cars traveling at
motorway speeds just before the crash, despite visibility that extended no further than 9 meters
(or around 30 feet). A pileup involving more than 130 vehicles was the inevitable result.
Fortunately, however, though there were extensive injuries and hundreds
of thousands of pounds worth of damage, nobody died in this particular incident.
Each of these massive multi-vehicle collisions was caused by the same basic mechanism:
a sudden change in weather conditions dramatically reduced visibility. This change
of conditions takes many forms in different accidents. On the 27th of February, 2014,
south of Barrie, Ontario, a 105-vehicle pileup was caused by a snowstorm. On the 2nd of December,
1994, intense glare from the sun on a rain wet road caused a 127-vehicle
pileup, and on the 9th of January, 2008, fog and the smoke from a nearby chemical fire mixed to
create zero visibility conditions on Interstate 4 in Florida, resulting in a 70-vehicle pileup.
Where roads are prone to foggy or dusty conditions it is possible to impose speed limits,
improved lighting, and warning signs to give drivers a chance to adjust... but all too
often these accidents are down to freak weather conditions that cannot be reasonably predicted.
This leaves only one line of defense against mass vehicle collisions: the behavior of drivers. Most
countries in the world have some variation on a rule of the road which states, essentially,
that drivers should drive according to conditions. In the UK, for example, drivers are instructed to
leave a minimum two second gap between themselves and the car in front, and to only ever drive at
a speed that will allow them to stop within the distance they can see. The problem is, of course,
that these rules generally aren't followed. Drivers tailgate. They drive at speeds higher
than conditions allow in order to keep up with traffic, to get where they're going faster, or
simply because they underestimate the time it will take them to stop if they need to. These are all
behaviors which aren't really a problem... until something happens, and they very suddenly are.