Cash Cow is right!
50kph is totally unnecessary there and 80kph just before it the same - it's a dual carriage way. They're also often on the other side of the roundabout where the bus-stop is getting people coming out of town.
The N81 by contrast is single lane with loads of bad bends and poor surfacing and is posted at 100kph.
Assigned speeds are a joke!
BTW... Today that van was parked on the grass verge at Palmerstown - just before the garage. 60kph there even though it is a dual carriage way. I was fine today, but got two fines there about 5 years ago - notorious spot apparently as all 80kph except for the little bit between the ESSO and the M50 ramp. Nothing to do with safety as never any accidents there... just about the $$$.