By Cormac Murphy

Wednesday July 16 2008

Fixed speed cameras used by gardai cannot distinguish between a car and a truck.
This device design flaw means that as long as lorries or buses obey the road speed limit the cameras will not detect the heavier vehicles breaking their specific limit of 80km/h.
Gardai have sought to concentrate the use of fixed Gatso cameras on roads such as the N4 as it enters Dublin where the overall speed limit is 80km/h.
However, at least four other locations on approach roads to Dublin where fixed cameras are used have 100km/h limits.
Assistant Commissioner Eddie Rock, head of the Garda Traffic Corps, said cameras in eight new Gatso vans would be able to distinguish between a car and a truck by measuring the vehicle's length. They hit the road next month.
However, Mr Rock said the three existing Gatso units were unable to take more than one reading.
He said the Gatsos currently used by gardai are "coming to the end of their life cycle" and the level of enforcement they were providing was lower than in previous years.
More than 231,300 fixed charge notices have been issued by gardai this year. A recent Free Speed Survey, carried out for the Road Safety Authority (RSA), found that 87pc of articulated lorries break the 80km/h limit on national routes.
The limitations in the Gatso equipment emerged as gardai launched a speed enforcement operation targeting lorries.
RSA chief Noel Brett was asked if there was a link between the high incidence of lorries and coaches speeding in the Free Speeds Survey and the limitations of the fixed cameras.
He replied that if "motorists believe the enforcement is unable to detect them, obviously they may choose not to obey the limits".
- Cormac Murphy