130kmph instead of 120kmph on motorway

120 average. From junction 17 or 18 at portlaoise to junction 11 on M8 there's no congestion whatsoever and the same applies when continuing on until I hit the 100kph limit on the old glanmire bypass. The only time to momentarily slow down is going through the express lane at the tolls. Having driven to/from Dublin on the M7 regularly, a consistent 120 can be done all the way to/from Waterford, Cork and Limerick from/to junction 11 on the M7. However from that junction there on in towards Dublin it gets congested fairly quickly.

The entirety of the M9, M7 from Junction 11 to Limerick and M8 until you reach junction 18 could be increased to 130 were tractors banned from the network.

Does it matter what the highway configuration is?

I’m telling you that the speed at which you travel in a vehicle dictates dangerousness. That’s not too hardcore for you is it?

My take is the gains are only noticeable on very long drives, and at that distance, any stops to refuel, eat, or use the loo make it useless.

I do the Cork to Dundalk drive once a month, I've never gotten under 3 and a half hours. Once I hit Naas I'm into traffic and it's impossible to maintain 120kphm. It is barely possible to maintain 100kph without weaving between slower cars using the incorrect lane, and that continues until past the airport. All bets are off at rush hour, and the near daily crashes on the M50.

With tractors the closing speed can be problematic even travelling at 120.

Why exactly do we allow tractors on motorways ?

It would seem obvious that the majority of their work is off motorways and the locations of that work are served by other roads.

We're only a small country with short roads, I don't see the point? cut 10 minutes out of my once in a year road trip to the other side of the country?

Rather than upping the limit I'd say focus on making sure people can go that 120kmh because most of the time there's fat chance of that.

That's an absolutely nonsensical argument. You've already seen the numbers around how little difference a change like this would be on long long motorway journeys ....the difference would be miniscule on far shorter journeys.

Lots of people commute large distances to their workplaces or indeed lots of people travel exclusively for work, there are far more things that can be done to enhance their lives/jobs that don't include a 10km increase in speed limits on the lowest density roads in the country.

Raising the limit by 10 km/h is a bogus suggestion to start with. Even the pitifully small projected time savings are based on some kind of fantasy universe where average speed equals the posted limit.

Raising limits on roads where those speeds are not attainable reduces traffic flow overall. This phenomenon is the reason why Variable Speed Limits (VSL) exist: like it or not, drivers treat the number on the signs as a recommendation, not a limit. If you tell someone "130" instead of "120" on a stetch of road where traffic volume has already limited speeds to 110, then the overall effect will be an even lower average travel speed, with uneven flow.

The only way this measure could work is as part of a national rollout of VSL on the entire motorway network, but I don't think that's what the OP is looking for, as it would result in lower limits than 120 applying in bad weather or busy periods.