It is the next step on from a Learners. A P plate is a provisional licence which may have restrictions that a full licence does not e.g. not allowed to carry passengers or drive during hours of darkness. The plates must be displayed on the front and rear of your car and there are 2 colors - red and green. This goes on for a couple of years unless you accrue enough violation points then you get to start again. I hate to admit it but whether it is due to this system or not Aussies are pretty decent drivers - not quite up to New Zealand's standards though.