Marc Ó Cathasaigh (Waterford, Green Party) | Oireachtas source

This is an extremely important issue. As I said, there are three elements involved, namely, road safety, climate implications and the implications for active travel. I do not know whether the Minister of State took physics for the leaving certificate but I apologise if I am giving him a flashback. The equation that governs kinetic energy is E = mv². It is the v² in particular that is the kicker on this one. It refers to velocity squared. We know the figures on road deaths. If a road user, such as a pedestrian or my 11-year-old child, is struck by a car travelling at 30 km/h, in one in ten cases, the person struck at that speed will die. If that same car is travelling at 50 km/h, five in ten people who are struck at that speed will die. If the car is travelling at 60 km/h - despite our default speed limits, it is not uncommon to see cars travelling in our urban environments at such speeds - nine in ten people struck at that speed will die. There is a real public safety element here that we have to face up to and address.

See this speech in context