Dublin’s M50 to get overhaul with overhead gantries and variable speed limits

New system can close lanes and reduce speeds in the event of a crash or bad weather

Dublin’s M50 is set to become a “dynamic motorway” with variable speed limits determined by computer algorithms and the ability to close individual lanes and junctions using “Red X” signals on almost 100 overhead gantries.

A major publicity campaign to inform drivers of how to interpret and respond to the new regime is to be launched in late June or July.

The Enhanced Motorway Operation Service (Emos) system will control 380 “dynamic lane signs” on 98 gantries over 38km of the M50. It will be able to close lanes and reduce traffic speeds in the event of a crash or severe weather events.

One of the key aims of the €80 million Emos upgrade will be to get more vehicles along the motorway per hour, particularly at congested times, by reducing the overall speed of traffic on the route.


Another is to ensure the safety of 350,000 vehicle trips per day, as well as the safety of first responders in the event of a crash.

Fibre optic cabling, connecting to road-side weather stations and traffic sensors, along with visual feeds will transmit information to the computers at the TII’s Motorway Control Centre in Dublin’s Docklands.

The computer algorithms will then be used to determine the need for lane closures or optimum speeds of traffic allowing controllers to intervene swiftly when congestion builds up or weather makes the top speed unsafe.

The computers will continuously run the algorithms to achieve the safest and most efficient operating conditions for 350,000 trips undertaken on the M50 every day.

Reduce congestion

Transport Infrastructure Ireland which manages the motorway has told the Oireachtas Committee on Transport that global experience has shown that managing traffic congestion by lowering speeds removes sudden braking and a resultant concertina-effect which can see traffic come to a halt.

The authority’s chief executive Peter Walsh told the Committee on Tuesday that such schemes were commonly used on motorways in the UK, in Continental Europe and in North America on the approaches to major cities. “The M25 around London and the M6/M40/M42 Birmingham Box and the motorways of the Netherlands are good examples.”

He said Emos system was needed here to address the increasing numbers of collisions and levels of congestion on the M50. In 2019, M50 operations crews attended 1,161 incidents, an average of 22 incidents each week of the year, and because “the M50 is congested”. In 2019, he said, an average of 350,000 trips were undertaken each day on the motorway, an increase of 40 percent on 2011 figures.

However he said the M50 would not be utilising the hard shoulder for traffic flow, as this had been shown to be a mistake abroad, leading to problems for emergency services in other countries.

Mr Walsh told the Committee TII could provide an online demonstration of what Emos could do, which may be appropriate given Covid-19 restrictions.

However Committee chairman Kieran O’Donnell said the committee would await the Government’s announcement of potential lifting of restrictions on Thursday, after which it may be possible to visit the control centre in person. “There is only so much you can do on Zoom”, he said.

The Committee was examining the Road Traffic (Miscellaneous Provisions) Bill 2019, which contains some measures required to implement the Emos system.

Mr Walsh told the committee these relate to giving TII the legal power to vary speed and to close lanes when needed. It also related to clarifying the power under which TII is to provide, manage and operate the Emos system. A further element required was for the bill to provide for appropriate enforcement, he said.

Tim O'Brien

Tim O'Brien

Tim O'Brien is an Irish Times journalist