MORE than 45 million vehicles crossed between Northern Ireland and the Republic last year, with the porous border seeing unprecedented amounts of traffic.
Details of cross border movements were contained in a new report on behalf of the Department for the Economy's Analytical Services Division.
It was issued by the department's EU Exit Analysis Branch.
The data shows the number of journeys in both directions climbing steadily over the last four years, from around 38.5 million in 2014.
There were more than a million more journeys recorded last year alone.
ANALYSIS: Cross-border vehicle figures make for sober reading
The vast majority of journeys were taken by car, with almost 36m crossings in personal motor vehicles between July 2017 and August 2018.
Meanwhile, freight traffic - likely to be a key focus of border inspection should the north exit the customs union and single market in a `hard Brexit' - accounts for 785,692 journeys recorded.
The data collected by statisticians is from the Transport Infrastructure Ireland traffic counters located on the National Road Network of Ireland.
It relates to just 15 of the separate border locations which provide entry between the two jurisdictions and the officials stressed it should be regarded as "subset of all border crossings and would not present full coverage of all vehicle border crossings".
Ireland has 208 border crossings, according to analysis carried out earlier this year - the first officially agreed count since the island was partitioned.
That joint mapping exercise involving the Republic's Department of Transport and the north's Department for Infrastructure.
It showed the border runs along the middle of 11 roads - more than twice the number originally believed - and meets in the middle of at least three bridges and dissects two ferry crossings.
The quantifying of the sheer scale of border vehicle crossings is likely to increase pressure in the last ditch negotiations currently underway to attempt to prevent the UK crashing out of the EU without a bespoke trade deal.
The issue of the border has proved a major sticking point in the negotiations, with the British government and their DUP allies standing firm on a refusal to countenance a `border' in the Irish Sea, arguing it would weaken the union.
However, the EU, in support of the Republic, is insisting on a fully detailed and workable `backstop' solution, which would ensure the border remains compliant with all articles of the Good Friday Agreement.
The fifteen border locations are:
N01 North of Jn20 Jonesborough, Ravensdale, Co Louth
N01 Between Jn9 Ravensdale and jn20 Jonesborough (Northbound), Ravensdale, Co Louth
N53 between NI Border and Castleblaney, Drumgoose, Co Monaghan
N02 between Castleblaney and Monaghan Town, Clontibert, Co Monaghan
N12 Armagh Road, Between N02 and R213
N02 between NI border and Emyvale, Mullinderg, Co Monaghan
N54 between Smithborough and Clones, Stranagarvey, Co Monaghan
N54 between Butlers Bridge and Clones, Clonoony, Co Monaghan
N03 between Belturbet and George Mitchell Bridge at NI border, Belturbet, Co Cavan
N87 between Ballyconnel and NI birder, North of Swanlinbar, Co Cavan
N16 between Enniskillen and Sligo, McNean Court, Co Sligo
N03 between Belleek and Ballyshannon, Templenew, Co Donegal
N15 Lifford to Castlefinn, Inchenagh, Co Donegal
N14 between Lifford and Letterkenny, Drumbuoy, Co Donegal
N13 between Bridgend and Burnfoot, Co Donegal
