So imagine you're a law abiding citizen - you're driving through your suburb at 60Km/h and a teenager with headphones on looking at his phone steps into the road, doesn't see you and you don't have time to stop. You slam on breaks but drive into him, doing damage to the teen, your car and possibly you.
Now imagine you're a law abiding citizen - you're driving through your suburb at 30Km/h and a teenager with headphones on looking at her phone steps into the road, doesn't see you and you don't have time to stop. You slam on breaks, drive into her, doing damage to the teen, your car and possibly you.
In which scenario are you, your car and the teen likely to get away without injury, or with less injury (also keeping in mind how much the car slows down and how long it takes to come to a stop from 60km/h vs 30km/h)
Is it your fault? No (maybe shared responsibility - you could have been more aware of your surroundings but let's say no in this case, it wasn't your fault) - the teen should have been aware of their surroundings and not just stepped into the road. How would you feel if you killed them though, even if it wasn't your fault? So I don't see blame and whose fault it is as so important as the fact that if you do hit a pedestrian you would much rather be going slower when you do.