Camera precaution: what can be done to stop migrant deaths in lorries?

In light of the recent tragic deaths of 39 people whose bodies were found in a refrigerated lorry in Essex, UK, is there any technology that could help stop this happening? Could truck companies install cameras to make sure there is no one inside, for instance? Mike ClarkeCastle Hedingham, Essex, UK

The easiest way to detect people in a confined space is to monitor carbon dioxide. Any concentration above the normal atmospheric level of about 400 parts per million would indicate that someone or something is respiring inside. A person typically breathes out about 24 litres an hour of CO2, so even one person in a standard empty shipping container would increase the CO2 concentration by around 500 ppm within an hour.

In a part-filled container, this would happen sooner. Even with a slight draught, it should be possible to detect a person after a couple of hours. The problem is that anyone smuggling people would just disable any detectors, unless a sealed data logger was required to provide a history.

Chris DanielGlan Conwy, Clywd, UK Several technologies are already available, such as cameras and CO2 sensors.

Acoustic sensors placed against a metal wall, say of a shipping container, can detect a movement on the other side as small as a few millimetres, such as a person breathing. X-ray scanners have been used on the US-Mexico border and at English Channel ports, although their use to detect people on the French side has been banned by the authorities as the law requires written consent from anyone before they are subjected to radiation. But many of these methods are time-consuming and impractical for use at busy ports.

More recently, a thermal imaging technique has been designed to scan for body heat inside trucks. This can scan around 250 vehicles per hour while they are moving. Determined migrants will always look to outwit any system, and smuggling or trafficking is hard to detect unless all vehicles are routinely scanned.

But, used well, such systems can save lives. Hillary J. ShawNewport, Shropshire, UK

The Victorians had an answer. They feared being wrongly declared dead and waking up buried alive, so had safety coffins[1] with an alarm - usually a bell, maybe electric - for someone to sound in this event. Since nobody might be watching a camera, or hear an alarm in a noisy lorry, how about a red flashing alarm light fitted outside the lorry, with a switch inside.

It would all be powered by the electricity that cools the freezer, with a back-up battery. This technology, which should be cheap, could also save lives when children get shut in discarded domestic fridges. To answer this question - or ask a new one - email [email protected][2].

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References

  1. ^ safety coffins (www.ancientpages.com)
  2. ^ [email protected] (www.newscientist.com)
  3. ^ Terms and conditions apply (www.newscientist.com)

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