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Message for the Highways Agency. 26/4/04
The Highways Agency has begun work on an Active Traffic Management pilot scheme designed to improve the throughput of traffic on a busy stretch of the M42 outside Birmingham in England. Amongst the initiatives to be examined as part of the project are ramp metering and hard-shoulder running, the second of which is to be introduced in the summer of 2005. The first stage of the pilot is due to begin this summer.

Controlling the flow of traffic will be specially designed, lightweight matrix indicators, known as an AMI (Advanced Motorway Indicator) linked to roadside controllers and using LED technology. Mounted on overhead gantries and spanning eight lanes of roadway, the fully populated 32 x 32 AMIs will be lane specific and capable of producing a range of instructions. A ring of red LEDs surrounding the matrix permits any sign to be made mandatory and, when illuminated, is likely to be linked to enforcement cameras.

Further enhancement mean that not only will the signs be visible in bright sunshine but that if a group of pixels were to fail, the display would be automatically shifted to another area, obviating the need to switch of the sign off while awaiting repair.

The Highways Agency will be placing the gantries at 500 metre intervals along the motorway, alongside emergency refuge areas off the hard shoulder.

"One of the problems we faced," said Ian Gibson of Colas, one of two companies that won contracts for the supply of the AMIs, "was the need to keep the load on each gantry to a minimum since there is no central pillar. One of the ways in which we did this was to remove a lot of the electronics and 'intelligence' from the indicator and house it in a roadside controller."

A single controller will deal with up to 16 indicators and is linked to the motorway communications system, explained Gibson. And since all diagnostic and performance related information is housed in the roadside cabinet, engineers are able to perform most routine functions without the need for climbing the gantries.

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For further information contact:
Ian Gibson of Colas. Tel: #44 1273 815 835, Mob: #44 7970 215 880
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