One of the ways to improve safety (work place, air-lines, mines, anything) is to have rules to stop people from committing dangerous acts, but rules on their own are useless unless they are enforced, so all normal safety systems have an enforcement element.
The road code is one of the systems to reduce the inherent danger of driving (along with crash barriers, WOF, street lights, brake lights, air-bags etc), however the rules aren't really enforced in NZ, so the the road code and licencing system is a farce - which is reflected in Auckland's sky-rocketing road toll.
If the police don't believe enforcing laws is a core police duty then it is high time to reconsider what taxes are being spent on. Traffic Police were once a thing and the message from police seems to be that they need to be a thing again.
This reducing speed limits on 1,000 roads to 30 kph is complete bollix. If everyone drives at 30kph then yes, the skyrocketing number of collisions will naturally produce fewer fatalities but the problem isn't the speed of the collisions, the problem is the collisions that never used to happen (at such high rates) and should not be happening now. This solution to road safety if taken to its ultimate destination is to have a speed limit of zero kph. Who is the genius who thinks that someone who ignores the road code is going to obey speed limits? Yes camera's everywhere will force people to drive at 30 kph, but would it be better if everyone drove properly in the first place and we got the people off the road who can't obey the road code?