Two large gantries have been constructed across both carriageways of the M50.
Equipment on the first gantry detects an approaching vehicle and activates equipment on the second gantry. This equipment detects whether a vehicle has an electronic tag and, if so, reads information on it. Cameras on the gantries can also photograph number-plate details of passing vehicles.
The information obtained by either method is used to debit the appropriate toll from a pre- established user account.
Where no account has been established, the system records the passage as a toll waiting to be paid. In this case, the driver must pay online, or through a call centre or local newsagents by 8pm the following evening.
Where no payment is made, the owner can be traced through the national vehicle driver database. Fines of over €140 may apply, though it may be harder to trace foreign-owned vehicles.
What it costs
It currently costs €1.90 to cross the West-Link, but this is set to rise to €2 in January.
Under barrier-free tolling to be introduced next August, the National Roads Authority proposes to keep the toll at €2 for motorists who use an electronic tag. However, there are other costs involved in the use of such tags; for example, the EazyPass system currently in operation for the West-Link involves a monthly administration fee of €1.21, a top-up threshold of €12.70 and a minimum top-up amount of €40. The tag itself is free but there is a charge if you lose it.
Motorists who don't want to use a tag can opt to create a payment account with the NRA, which will track their usage of the M50 using number plate recognition technology. The toll here is €2.50 for cars, reflecting the extra effort involved.
Occasional M50 users who don't use a tag or register will have to pay €3 a trip.