Dublin, Cork, Galway, Limerick, Waterford
Sligo, Castlebar, Tralee, Wexford, Port Laoise, Athlone, Dundalk
These towns may/will not fit: Mullingar (could be scenery town), Clonmel (could be scenery town), Arklow, Kilkenny (too close to Waterford and Port Laoise), Dundalk (too close to Newry)
(Suggested) Scenery towns
Letterkenny (if it will fit - close to (London)derry), Charlestown, Tuam, Newcastle-West, Killarney, Macroom, Mallow, Tipperary, Youghal and/or Dungarvan, Birr, Longford, Carrick-on-Shannon, Carrick-on-Suir (not on map), Tullamore, [New Ross], [Enniscorthy]
Dublin Port (to Holyhead), Rosslare (to Fishguard/Pembroke & Roscoff/Cherbourg)
Motorways & National Roads
Obviously not all of these will fit, these are just the roads that lead to the places I've listed above.
M50 - Dublin ring road; include sDublin Port Tunnel & M50 Tolls (between J6 & J7 and Dublin Port Tunnel)
M1 - Dublin towards Northern Ireland; N1 after Dundalk
M4 - Dublin to around Kinnegad; N4 - Coralstown towards Sligo & entering Dublin
M6 - Kinnegad towards Galway; N6 around Athlone & entering Galway
M7 - Dublin towards Limerick; N7 entering Dublin after Naas; includes MidLink M7/M8 toll in Co. Laois
M8 - Dublin to Cork (via M7) (N8 entering Cork)
M9 - Dublin to Waterford (via M7); N9 near Waterford)
N10 - road from M9 to Kilkenny, forms part of ring road
M11 - Dublin to Wexford (N11 along some parts, including around Wexford)
N13 & N15 - Sligo towards Northern Ireland via Letterkenny
N16 - Sligo towards Northern Ireland (to Enniskillen)
M17 - Rathmorrissy Interchange to Tuam; N17 after Tuam towards Sligo
M18 - Limerick to Rathmorrissy Interchange; N18 around Limerick
N20 - Limerick to Cork; M20 near Limerick
N21 - M20 towards Tralee
N22 - Cork towards Tralee
N23 - Joins N21 & N22
N24 - Limerick towards Waterford via Clonmel
N25 - Cork towards Rosslare Harbour
N27 - N8 in Cork towards Cork Airport Business Park (but only needs to go as far as the N40)
[N30 - Enniscorthy towards New Ross]
N40 - forms southern part of Cork ring road
N52 - J26 M7 to Birr, Tullamore to J5 M6, J4 M6 to Mullingar
N60 - N17 towards Castlebar (could also add N5 as well or instead)
N62 - Birr to J8 M6
N77 - forms part of Kilkenny ring road, to Port Laoise
N80 - Port Laoise to Tullamore
[R723 - formerly N25, from Glenmore Roundabout through New Ross to Ballymacar Roundabout.] No need for this road, Google Maps has Street View for the new section of the N25.
[R772 - formerly N11, from the roundabout where the M11 joins the current N11 (towards Wexford) through Enniscorthy to Clogh Roundabout.] No need for this road, Google Maps has Street View for the new section of the M11.
Roads under construction/recently completed construction
M7 around Naas is being widened to 6 lanes (3+3) - has now been completed with one junction (future Sallins bypass) not yet opened - http://www.m7upgrade.com/
N25 New Ross bypass (including Rose Fitzgerald Kennedy Bridge) - completed in early 2019 - https://www.n25newross.ie/
M11 Gorey-Enniscorthy bypass - opened in July last year - https://www.m11gtoe.ie/
- Ireland is divided into 4 provinces (Munster, Leinster, Connacht & Ulster), which are further divided into counties (26 in ROI, 6 in NI). It would be nice to see these signs in-game. Examples: 1 & 2.
- Irish language is displayed on road signs (please don't ignore like the Welsh ones...)
- National roads (N1-N49) usually have hard shoulders, N50 onwards usually don't.
- Speed limits:
- Residential areas: 30km/h
- Built-up areas: 50km/h
- Local (L) & regional (R) roads: 80km/h
- National (N) roads: 100km/h (80km/h for vehicles over 3.5 tonnes)
- Motorways (M): 120km/h (90km/h for vehicles over 3.5 tonnes) (with the exception of the M50 - 100km/h)
- In addition to these speed limits, please do not use this sign as either an indication of "end of restrictions" or "end of previous speed limit" - it simply doesn't exist in Ireland (a similar one is used but only for local roads). In its place should be a sign indicating the new speed limit.
- Road sign font is Transport Heavy on ALL signs, with additional characters for letters ('A', 'a', 'm', 'n' & formerly 'i') used in the italic Irish text (e.g. https://imgur.com/QtYZbs3).
- Route numbers (very very minor and unusual detail, but it is how it appears on signs - https://i.imgur.com/ImOGY0R.png) ((I understand if you don't include this ):
- Motorway route numbers written in "Motorway" font (like the UK)
- National route numbers written in "Transport Heavy", with the 'N' condensed
- Local route numbers written in Transport Heavy (L is not condensed)
- Regional route numbers written in Transport Heavy with the 'R' condensed
- On motorway signs, due to the lack of "N" and "R" characters, they are written in Transport Heavy (https://i.imgur.com/Yt6gMla.png). The numbers are written in Motorway (example 1), although this is very inconsistent (example 2).
- The majority of service stations are located off motorways - some notable ones include Barack Obama Plaza & Junction 14 Mayfield off the M7 & the Manor Stone Service Station off the M8.
- Police cars (Gardaí) - many different cars are used but most common are Hyundai i40 Tourer and Ford Mondeo Mk Ⅳ (like what is used in Finland).
- There are very little (if any) speed cameras in Ireland. Instead, there are usually "speed vans" (e.g. Ford Transit Custom & Fiat Ducato) located at the sides of roads (usually national - I've never seen any on motorways). On motorways, Garda cars are (very rarely) located in bays (marked with "Garda Only" signs [example]).
- Licence plates - see this Wikipedia article (notably "Format and specifications"). There is no specific font used (any sans serif font can be used). Charles Wright (like the UK or a lighter version) is quite common. Examples: 1, 2, 3, 4.
- Popular cars (that aren't yet in the game) include Hyundai Tucson, Volkswagen Passat, BMW M5 (~2013), Hyundai Kona,Volkswagen Golf Mk 5-7, Ford Kuga, Toyota Auris, Toyota Avensis (all types), Kia Sportage and Volkswagen Tiguan. In summary, cars from Toyota, Hyundai, Kia, Volkswagen and Ford, particularly SUV's and crossovers, are very popular.