Search the Vic section for threads, around fatalities sadly as there is a stack of info in some of them.
My thoughts summarised:
Restricting passengers isn't right, its knee jerk and has been thought up because of a minority. Uni students etc who house share and may only have one car, will have to make alternative arrangements, young people in jobs who can't all afford cars etc. Disagree completely with this one.
Better driving training is needed, it has to be a test not some baboon telling you "I will checking you obey stop signs, keep out of cycle lanes and observe the speed limit" as I witnessed at Vic Roads personally. A test should include multiple challenges e.g. I had to reverse around a corner and keep a certain distance from the kerb, while checking mirrors and not looking at the steering wheel as 1 example in the UK. Had 2 others to do also.
Definately limit the car, a young male or female does not need 11ty billion KW at the wheels. 50-100kw is ample. This is a vehicle to get you from A-B while you build up your experience. It need not be new, expensive or powerful.
Insurance that is related to the car should be mandatory. If people had to pay for an expensive or powerful car (mods declared), they would soon think twice about what they bought and the mods to it.
There will be more p platers on the road which could be both positive or negative. Negative, more inexperienced road users, positive, more $$ for the State with rego, fines etc.
Other factors that are not P plate related I feel are an issue include, lack of tolerance on speed on highways, roadside cameras, defecting.
Hope this helps.