The long-heralded speed detection cameras that calculate how fast a vehicle is travelling by measuring the time it takes to cover a specified distance will begin working shortly in Dublin's Port Tunnel.
Cameras have been installed at either end of the 4.5km-long north and south-bound bores in which there is an 80km/h speed limit.
Any vehicle photographed passing through the tunnels in less than three minutes and 20 seconds will be travelling faster than that limit.
The drivers of such vehicles will be liable to an €80 fine and three penalty points.
Speed-over-distance cameras operate successfully on many UK motorways and have been seen to have a strong deterrent effect on illegal driving.
These are the first such cameras in the Republic.
Tunnels by their very nature are notoriously dangerous, especially when fire breaks out.
Horizontal flue
Their design, with a single entrance and exit connected by what is in effect a horizontal flue, facilitates rapid combustion generating intense heat - far in excess of a fire of the same size outside a tunnel.
Sean O’Neill of Transport Infrastructure Ireland (TII) suggested the new anti-speeding measure would help maintain the Port Tunnel’s safety record.
“The tunnel is a contained environment,” he said on RTÉ’s News at One.
“If accidents happen it is difficult to get to people and you always want to be careful when dealing with tunnels. It is a motorway, part of the M50, and you want people to drive through there safely.”
The cameras are to become operational imminently.