Cork’s Dunkettle Interchange to be fully free flow from today

Work on the junction which handles more than 100,000 vehicle movements a day on the main approach routes to Cork city from Dublin and Waterford, has been described as akin to performing open heart surgery on a patient—while they are awake.

Several link roads have opened since the first one in February 2022 took M8 southbound traffic on a new route to the tunnel—including three in October 2022, four the following month, two of which are set to be busiest when the scheme is complete, and another link road into Little Island in February 2023.

But this weekend’s changes are the most significant on the scheme to date, with potential impacts for some 40,000 vehicle movements a day, with new lane layouts and journey flows for traffic approaching from the north, south, east and west.

Project resident engineer, Kieran Lehane, said they have never opened so many critically important links on the scheme to so much traffic in such a short space of time.

“The links we are opening on Sunday are some of the most strategically important on the scheme because they will take most of the traffic,” he said. “And we are also turning off the traffic lights. So this event really marks a significant milestone on the scheme to date.

“It effectively creates a fully free-flow interchange, which is what the scheme was designed to do.” 

Mr Lehane and his team of engineers from Jacobs and Sisk, who are delivering the project for Transport Infrastructure Ireland, are now finalising a complex and highly co-ordinated traffic management operation that will start on Thursday.

Construction crews will then work 24-hours a day to get everything ready for the simultaneous link road openings over the space of a few hours on Sunday morning.

Significant enabling works are required first, including the closure of the R623 western exit from Little Island on Thursday night, the relocation of several lanes of traffic, the construction of one entire section of new road between Little Island and the tunnel, while keeping traffic flowing.

The simultaneous link road openings have been scheduled to take place between 6am and 10am on Sunday when traffic volumes are expected to be at their lowest.

Once the new links open and the traffic lights are switched off, motorists will be able to drive through the Dunkettle interchange without stopping at lights for the first time since the Jack Lynch tunnel opened to traffic in 1999. 

The link roads due to open to traffic from Sunday include:

• Link B will provide a new free-flow link for motorists on the N40 South Ring Road using the tunnel northbound and who want to head towards Cork City, via the N25/N8 westbound. This link will be used by about 6,000 vehicles a day
• Link F will provide a new free-flow link for motorists coming from Cork City on the N8/N25 eastbound and who want to access the Jack Lynch Tunnel. This link will be used by about 7,000 vehicles a day. Engineers have urged people to adhere to the speed limit on the loop which feeds motorists toward the tunnel
• Link J will accommodate motorists on the N25 westbound who want to access Little Island. This link will provide a second access to Little Island and will be particularly useful for businesses located in the western section of the industrial area. Engineers say the traffic volumes on this link can only be determined once the new road layout becomes established but they estimate that it will be able to accommodate more than 1,000 vehicles a day
• Link K will provide a new free-flow link for N25 westbound traffic wishing to access the Jack Lynch Tunnel. It will carry over 16,000 vehicles per day. It is opening with a temporary alignment
• Link L will provide access to Link K from Little Island and will cater for Little Island traffic wishing to access the Jack Lynch Tunnel. It will carry over 6,000 vehicles a day
• Link M will accommodate Little Island traffic wishing to access the N25 westbound. It will also form part of the new access route for southbound traffic on the M8 wishing to access Cork city centre via the N8. Engineers expect this road to carry about 3,000 vehicles a day. It is also opening with a temporary alignment. Link M will also temporarily accommodate N25 westbound traffic wishing to access the M8 northbound, and Little Island traffic wishing to access the M8 northbound, by directing them towards the Tivoli roundabout.

This short-term arrangement, which will add a little extra distance to these journeys, will be in place until link C is opened to traffic later this year.

In the meantime, an additional 2,000 vehicles a day will use the recently resurfaced Tivoli roundabout. Engineers plan to closely monitor the operation of the traffic lights at this roundabout over the coming weeks and make changes if required.

All six new links are expected to significantly improve traffic flow through the interchange for a number of journeys but especially for motorists heading for Dublin, those using the N40 northbound through the tunnel and who want to head westbound on the N8 towards the city centre, and N40 traffic heading eastbound on the N25 for Carrigtwohill and Midleton, or the Little Island area, via a fully free-flowing Link A.

The opening of Links K and L will significantly improve traffic flow on the N25 westbound between Little Island and the Jack Lynch tunnel—one of the largest single traffic movements thought the interchange, accommodating over 25,000 vehicles per day.

The closure of the R623 western exit from Thursday will mean traffic coming from Little Island traffic wishing to access the Jack Lynch tunnel will have to use junction 2 at the Little Island interchange.

“We have engaged fully with Little Island businesses in relation to this temporary arrangement and we expect that traffic volumes during the AM and PM peaks on Friday will be much reduced,” Mer Lehane said. 

“Nevertheless, additional time should be allowed for the journey from Little Island to the Tunnel during the R623 closure period.” 

While several sets of traffic lights at several locations across the Dunkettle interchange will be switched off on Sunday, just one set of traffic lights will remain in place for about four weeks at the northwest corner of the interchange roundabout.

“This will be an on-demand light to facilitate access for construction works traffic and will only be utilised during off-peak times,” Mr Lehane said.

“The northwest corner of the interchange roundabout will provide free flow for both Link A and Link D northbound traffic during peak times.” 

Intensive works in the area of the existing interchange roundabout will continue on a number of links over the coming weeks.

Engineers expect to have Links K, M, B, and A fully complete by August.

Traffic volumes at the interchange are continuing to increase, reaching approximately 110,000 vehicles per day on the busiest days of the week.

Roads appeal

Dunkettle engineers have issued a special road safety appeal ahead of this weekend's mass road opening event.

Strict traffic management operations will be in effect from Saturday night, with the new link road openings due to begin from 6am on Sunday.

Gardaí and three speed vans will be in place to enforce the reduced speed limits in the area which are in place to ensure the safety of motorists and to protect the construction workers on site.

Kieran Lehane, the project resident engineer, appealed to motorists to reduce their speed through the interchange this weekend, and to exercise caution and consideration as people familiarise themselves with the new road layouts.

He said motorists who have grown familiar with following certain routes through the interchange will need time to get used to the new road and lane layouts, and with perhaps having to follow a new route on their journey through the interchange.

Motorists have also been advised to plan their routes in advance, and to disregard directions from Google Maps or their own satnav systems in relation to the new interchange, and to focus instead on following the road signs and diversion information.

Engineers are liaising with Google as the various road openings take effect to ensure that the online mapping service has the most up-to-date information possible reflected on its online maps.

Some of the current road layouts are in place temporarily while work continues to complete the remaining links over the coming months.

You can get detailed route map information, and updates on future link openings and diversions from dunkettle.ie.