A PLANNED new speed detection system to help save lives in Dublin's Port Tunnel has been shot down by transport chiefs.
Drivers breaking the limits on the €751m motorway are likely to continue to go unpunished following the move.
The National Roads Authority (NRA) had sought to install the equipment to catch dangerous motorists.
But the Department of Transport withheld approval for the scheme on the basis that enforcement of the limits is a matter for the gardai.
It is understood that, while gardai mount speed-checks in the areas outside the tunnel, they do not generally do so within the underpass.
An NRA source told the Herald that the organisation has been "concerned about speeding" in the tunnel.
"We would speak to the gardai but they would be looking at the areas outside, which they have been doing," the source said.
It is an operational matter for the gardai where they chose to stage speed checks.
The source said the NRA wants the detection to be carried out in the tunnel but "it is the garda's call".
While surveillance and safety cameras have been installed, they are not of a sufficient quality for use as evidence in speeding prosecutions.
Tenders for a speed detection and control system in the tunnel were advertised in the European Journal last March and the final tender deadline was set for August.
However, the NRA -- which was to finance the new system -- confirmed the process has now been abandoned.
Issues surrounding driver behaviour in the tunnel have been highlighted on a number of occasions.
In 2008, a motorist was charged in connection with an incident in which a car went through the underpass the wrong way.