How Ireland's first 'distance over time' speed trap will work
Drivers using Dublin's Port Tunnel will have their average speed clocked as they travel underneath the city, to see if they are breaking the speed limit.
Special cameras will allow tunnel bosses to determine if motorists are breaking the posted speed limit of 80kmh, and those found to be in breach will be fined €80 for speeding and get three penalty points on their licence.
The new system will become operational in the autumn - and is being introduced amid concern that higher traffic volumes in the 4.5km tunnel are posing an increased risk of accidents or collisions.
Transport Infrastructure Ireland (TII), which manages our roads and railways, says that almost 24,000 vehicles a day use the tunnel now, compared with 16,439 in 2012 - an increase of 40pc.
"We welcome this enhancement to the operations of the Dublin Port Tunnel," said Chief Superintendent Aidan Reid from the Garda National Traffic Bureau.
"Due to an increase in traffic travelling through Dublin Port Tunnel, this new enforcement system provides additional support toward maintaining a safe travel experience for all users."
Special cameras mounted on large yellow poles, which are being erected today, note the registration plate of each vehicle as it enters and exits the tunnel. The journey time is expected to be around three minutes and 30 seconds if the speed limit is obeyed.
A computer can thus calculate whether a car has been speeding in the tunnel. A record will then be transmitted to the gardaí who issue the fine and penalty points.
The system is commonly used in other European countries in an effort to reduce collision rates on busy roads. It is also increasingly being deployed at roadworks, and research suggests use of the average speed detection system can reduce collision rates by up to 50pc.
TII said the average speed would be recorded between two camera positions that covered all lanes. Switching lanes would have no effect on average speed monitoring, it said.
Chief executive Michael Nolan added that the system would help maintain the tunnel's "strong" safety record.
Testing is expected to get under way shortly, and the system will go live in the autumn. It will operate around the clock.
Drivers who receive the fixed charge fine of €80, together with three penalty points, have 28 days to pay. If not paid, it increases to €120. A court summons is issued if left unpaid for 56 days, and five points are applied and fines of up to €1,000 can be imposed.
The Dublin Tunnel opened in December 2006.