Keeping over-height and overheating vehicles out of tunnels

On the other side of the world a fire in the Sydney Harbour Tunnel (SHT) was the initial incentive for developing a laser-generated Softstop ‘water curtain’ STOP sign, subsequently routinely used to deter overheight vehicles. Developed by Asia-Pacific special effects company Laservision, using events industry experience and hydraulic engineering technology, this creates a ‘barrier’ of last resort. The activated curtain carries a laser projection of a large, apparently solid ‘STOP’ sign at the portal to shock drivers that have ignored previous warnings to halt. It has enjoyed a 90% success rate.
Says tunnel general manager Bob Allen, who found Laservision through an internet search: “At the initial incident, drivers ignored conventional warnings and continued towards the fire. They exposed themselves to smoke and toxic fumes and then, to compound the situation, turned around and drove back out against incoming traffic.”