Virtual stop sign to cut tunnel risk

19th July 2007

UK tunnel operators are considering bringing in the startling new safety measure - a laser projection of the sign on to a sheet of water sprayed from pipes above - to prevent drivers getting caught in underground incidents.

The giant red and white symbol appears like magic in front of the entrance as soon as a fire or collision is detected inside. Crucially, when it's switched on, the instant barrier poses no danger to motorists who are not able to pull up in time. So any car that is too close to the curtain of water can pass right through without damage - as can any emergency vehicles that are called to deal with the incident.

The first of these impossible-to-miss safety systems has recently been installed at the entrance to the Sydney Harbour Tunnel in Australia, and now, the European distributor hopes that it could soon feature on the British road network. "We presented it to a forum for tunnel managers, and they are showing interest," revealed Harold Trunley, boss of Vital Technology, based in Manchester. "Civil engineering consultants who are responsible for tunnel safety in this country have also taken a look at it," he added.

Trunley says the technology can even prevent hazardous incidents before they occur and help to keep the passages running freely. "Sensors that detect vehicles which are too high can also trigger the sign and stop them entering a tunnel where they'd cause damage," he explained.

The sophisticated virtual barrier comes at a price - about £200,000 - but experts say it could pay for itself by saving lives and keeping vital transport arteries flowing.