Er, dgp was blaming the PM for idiots being issued with driver's licences.
Given driver's licenses are issued by state authorities, the direction of blame is false. A national database has no bearing on how and when licenses are issued.
"Minor exceptions" is a pretty broad/loose term. Without comparing all of the statutes, as far as I am aware there are numerous differences/exceptions across states. Whether it be vehicle registration requirements such as the need for roadworthy cetificates and the frequency of same, the age at which a driver's license can be obtained, the restrictions applied to p platers (including engine type/capacity) or even the setting of speed limits and the margin over which one gets penalised just to name a few.
I am also not sure how the responsibility for and the source of funding to build particular types of roads is relevant to the original point.