I know nothing about the infrastructure in Ireland, but the drivers in the US kill at least twice as many people. Letting people drive cars at 50 km/h in an urban area is crazy, everyone you hit at those speeds die.
I suspect it's well more than 2x the people, Ireland is only 5.5 mil total (essentially the size of Washington State).
We've got rural roads that are slightly more than one car wide, some with grass growing down the middle, and are signposted for 80kph. We've got motorways at 120kph.
They just lowered it in Paris to 30km/h. Lower speed is directly correlated with less crashes. The other benefit is less noise, which is very important in an urban area. In most urban areas now the loudest most constant noise is from vehicles.
50KPH is the norm in any built up area, including in housing estates. Like a subdivision. That's 30mph, for a place where kids play in the green, cats dart out between parked cars, and there's tons of ped traffic.
