Mr. Michael Nolan:

The main reason for that is that from Maudlins in Naas to Newlands Cross, there is much uncontrolled access. There are garages and bus stops, and commercial business vehicles accessing and egressing the dual carriageway. On a motorway, there are controlled access points. They do not have petrol stations, quarries or bus stops. That is essentially the difference. A safety factor is coming into play with regard to the speed limit being 100 km/h rather than 120 km/h.