by Richard Gleeson
Northern News Services

NNSL (Sep 03/97) - It would be tough to convince some drivers, but the traffic lights in the city have a brain.

Focused exclusively on providing the most convenient phasing of lights, the network is controlled by a computer at city hall.

"All traffic lights all the way out to Old Airport Road are hooked into it," says public works director Neil Jamieson.

"This year the Byrne Road crossing, Range Lake Road and Borden Drive are being tied into it."

The computer system co-ordinates the timing of the traffic lights, to allow as uninterrupted a journey as possible for motorists.

The need for co-ordination has grown in the last five years, as the number of intersections with traffic lights has increased from seven to fifteen.

The city hall computer is linked to controllers -- contained within metal cabinets attached to traffic light poles -- that govern the timing of each light.

The system is sold and serviced by Intrex, of St. Albert, Alta.

Determining optimum phasing means taking into consideration which streets will get priority, drive time between intersections, how long to allow for pedestrians crossing the road, and also listening to the people who encounter the lights on a daily basis.

"People really notice changes in timings," said Jamieson.

As an example, he said, people have said there was not enough time to walk across one street before the light changed.

"We've gone and checked and, sure enough, the timing was not the same as all the other ones."

The system is complemented by sensing devices buried under side streets where they intersect with main streets.

"They're just basically a loop of wire," explained Jamieson. "A current goes through that creates a magnetic field. When a vehicle comes over it, the metal in it changes the magnetic field and triggers the timing of the light."

The controllers also have the capacity to allow for speedier and safer emergency responses.

Fire and police vehicles can be fit with devices that emit a beam that triggers traffic lights ahead to turn green.