Motorists seem likely to have to pay a new toll before accessing the upgraded M50 to stop traffic congestion on the road, it has emerged at an inquiry by An Bord Pleanála.
The benefits of reduced traffic congestion from the proposed widening and upgrade of the M50 will be eroded if "demand management" measures to deter motorists from unnecessary use of the road are not implemented, Mr Gordon Henderson, transport planner for the upgrade, said.
"The scheme will deliver very significant benefits from the outset, in terms of time savings and reductions in traffic congestion. In the longer term, however, traffic growth will erode these benefits if nothing is done to preserve them," he said.
Widening the M50 to three lanes along 31 km and upgrading 10 of the access points or "interchanges" along its route is intended to reduce the average travel time by 19 per cent in 2008 and 11 per cent in 2023.
"To lock in the benefits from this major asset it is planned to implement scheme specific demand management measures to control the level of future traffic growth on the motorway," he said.
The measures could take the form of physical deterrent, such as traffic lights leading on to the access ramp, or a pricing mechanism, i.e. tolling all cars before they enter the M50.
The exact measure will not be chosen until the new road is completed and extent of the need for demand management can be assessed, Mr Henderson said. However, he added: "from my personal point of view the pricing option is preferable."
Mr Henderson's views were echoed at the hearing yesterday by the director of the Dublin Transport Office, Mr John Henry.
Trying to control access to the road by traffic lights could shift congestion into the surrounding suburbs and national roads. "People will travel with the hope of getting on to the M50."
However, he said if motorists had to prepay a toll, they were likely to consider whether or not they needed to use the road.
Currently the toll is only paid at one point on the road, the West Link toll plaza, which means that motorists can use the M50 for free as long as they exit before that point. Tolling all cars before they enter the road would be done by a "free flow" mechanism, to prevent a traffic backlog. The exact mechanism has yet to be determined but it is likely to involve electronic monitoring of the cars as they enter the road.
