Just half of the Republic\u2019s 5,300km of motorways, national routes and secondary roads \u2013 regional and local roads are assessed separately \u2013 are designed to modern standards, according to analysis from Transport Infrastructure Ireland<\/a> (TII), the State agency that manages the roads network. <\/p>\n That leaves many vulnerable to the increasing levels of damage that might come from extreme rainfall, storms, heatwaves and intense cold. <\/p>\n Even modern infrastructure faces unforeseen hardships and will need retrofitting, TII\u2019s Climate Adaptation Implementation Plan states. <\/p>\n Against a backdrop of reduced investment in recent years, the task of maintaining the network to withstand extreme conditions has become more challenging.<\/p>\n \u201cCurrent funding levels are approximately 50 per cent of 2008 values,\u201d the report states. <\/p>\n \u201cThis decline significantly impacts TII\u2019s ability to adequately provide for baseline road maintenance, which is a critical enabler of climate adaptation and resilience.\u201d<\/p>\n The risks and where they are most likely to occur require greater investigation to find the most accurate projections, the report states. <\/p>\n However, some expected impacts are already identified. Just over 300km of national roads \u2013 one in every 18km \u2013 is exposed to future flooding under the current outlook for climate change. That\u2019s six times more than has flooded to date. <\/p>\n Along those 300km, structures at risk include 688 bridges, 128 culverts, eight underpasses and four gantries. <\/p>\n While the M7 on the Dublin-Kildare border flooded in 2020 and 2024, and the M4 near Maynooth in 2017, newer roads such as these motorways generally withstand severe weather. <\/p>\n The M50 ring-road around Dublin has also coped ably, having had no major flooding. Notably, it remained open during the five days of heavy snowfall accompanying Storm Emma in 2018. <\/p>\n But the report states that it too is at risk as the impacts of climate change worsen. <\/p>\n [\u00a0Why are flood defences taking so long to build? Don\u2019t blame the pearl musselOpens in new window<\/a>\u00a0]<\/p>\n \u201cIt is unlikely that TII\u2019s current maintenance measures will be sufficient to address rainfall and flood impacts under future climate,\u201d it says of the route. <\/p>\n Some of the newest stretches of national road may also need attention. <\/p>\n At almost a kilometre long spanning the river Barrow estuary, the Rose Fitzgerald Kennedy Bridge on the N25 connecting Wexford and Kilkenny has won awards but it has had to close to traffic several times since opening in 2020 because of high winds. <\/p>\n That bridge and two others \u2013 the M8 Blackwater Viaduct near Fermoy and the N25 Thomas Francis Meagher Bridge connecting Waterford and Kilkenny \u2013 need assessing to see \u201cwhether there is a case for retrofitting wind shielding on these structures\u201d. <\/p>\n The M50 West Link and the M1 Mary McAleese Boyne Valley Bridge are already wind-shielded but as high, long-span exposed bridges, they are considered susceptible in harsher future conditions. <\/p>\n TII\u2019s most widespread concern is the 50 per cent of \u201clegacy\u201d roads that are \u201cnot designed to modern standards, either in terms of alignment, pavement construction or drainage provision\u201d. <\/p>\n That leaves them prone to blockage and damage from various flooding sources, from sudden intense downpours to gradual groundwater rise from prolonged persistent rain. <\/p>\n Of particular concern are \u201clifeline roads\u201d such as the N56 in Donegal, the N59 in Galway and Mayo and the N71 and N86 in Kerry that serve rural areas with no alternative routes. <\/p>\n \u201cIreland\u2019s lifeline roads are in regions with the most rainfall and largest projected increases, making them more vulnerable to disruption from flooding, bridge or culvert washouts, and landslips,\u201d the report states. <\/p>\n Historical design parameters may no longer be appropriate in the face of the kind of extreme weather events that we are increasingly witnessing<\/p>\n \u2014 \u00a0 Transport Infrastructure Ireland<\/p><\/blockquote>\n Also highlighted are various spots along the N5, N63, N67 and M18 in Clare, Galway and Roscommon which are low-lying and prone to groundwater flooding. <\/p>\n Coastal flooding is not a big concern as little of the national road network is close to the sea but some stretches are. <\/p>\n Most exposed is the N69 between Tarbert and Foynes which lies in the middle of a key route along the Shannon estuary connecting Tralee and Limerick city and is at risk from both sea level rise and storm surge. <\/p>\n Rising sea levels, storm surges and rainfall-related flooding are flagged as concerns for the Dublin Port, the Jack Lynch tunnel in Cork and the Limerick tunnel under the river Shannon. <\/p>\n![\"Flooding](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2026\/02\/LJDJUUOWSQ26L5UOBEJYWHPSQ4.jpg\")
Flooding in Carlow in December. Photograph: Niall Carson\/PA <\/p>\n![\"The](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2026\/02\/GD5SEG6PRLSJAD3DQWU72WBR4Y.jpg\")
The Rose Fitzgerald Kennedy Bridge over the river Barrow <\/p>\n![\"Ireland](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2026\/02\/1772286910_118_WLY2OV5RF5EYZITRZGQI7F34LA.jpg\")
Flooding in Clontarf Road in Dublin earlier this month. Photograph: Chris Maddaloni <\/p>\n\n
![\"Molls](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2026\/02\/AHJYNUMEBFBHZD5LCCX6TDZBVE.jpg\")
Molls Gap, Co Kerry. Photograph: iStock <\/p>\n