M50 to become a ‘managed motorway’ in major changes in response to traffic volumes

New controls to include variable speed limits and the ability to close lanes

Major changes to how traffic will use the M50 motorway in Dublin are due to be announced on Friday.

Under a €50 million plan to tackle increasing traffic volumes, the M50 is to become Ireland’s first “managed motorway” with controllers based in Dublin’s docklands being able to set variable speed limits, close lanes, divert traffic off the motorway and clear lanes for emergency vehicles.

Traffic numbers on the motorway rose 40 per cent between 2011 and 2019, and figures show that M50 traffic levels have returned to about 90 per cent of the June 2019 traffic levels.

Transport Infrastructure Ireland says the road facilitates the movement of up to €35 billion of goods each year, the movement of which must be actively managed to prevent costs in terms of delays and gridlock.


There are up to 400,000 trips on the M50 every day, it says, 40 per cent of which are during peak hours.

The busiest section is generally between the N2 interchange at Finglas and the N3 interchange at Blanchardstown.

TII said the typical trip for a regular M50 road user was less than two junctions. Some 44 per cent of M50 trips are less than 20km in distance, while 70 per cent are less than 30km.

In addition to the €50 million set-up costs, the new management system will cost €30 million to run over the next decade.

‘Dynamic service’

The authority said the investment would allow it to deliver a more efficient, flexible and dynamic service to road users.

The scheme will rely on almost 100 overhead gantries carrying 386 lane closure signals, with an additional 64 variable message signs and 45 CCTV cameras. The overhead lane control signals will be complemented by 54 slip road signs on the entry points to the M50.

Where necessary, traffic can be diverted from sections of the motorway, travelling along way-marked routes through the suburbs, to avoid incidents.

The scheme is being rolled out on a phased, incremental manner to allow road users, emergency responders and operators the opportunity to familiarise themselves with the new digital signs.

The system will begin this autumn with variable speed limits being displayed on overhead gantries, as guidance only, until motorists are familiar with the signs. The first section to display the signs will be Junction 4, Ballymun, to Junction 6, Castleknock.

Early next year, additional phases will be introduced, with the extension of the signs from Castleknock to Junction 9, Red Cow. By next summer, the scheme will cover the M50 as far as Firhouse, and by autumn 2022 it will reach Junction 14, Sandyford. The last phase will include Sandyford to the M11 and Junction 3 M1 to Ballymun.

To allow road users a period of time to familiarise themselves with the new digital signs, the variable speeds displayed on overhead gantries will initially be cautionary. Road users are reminded that, during this period, the existing speed limit of 100km/h on the M50 remains enforceable, in line with the static signage along the motorway.

The Road Safety Authority is to roll out a public awareness campaign to make drivers aware of the introduction of the new speed signs on the M50 and why they are being introduced.

Tim O'Brien

Tim O'Brien

Tim O'Brien is an Irish Times journalist