There was discussion on the radio today and it appears the police want more unmarked police cars to catch the "bad" (my word) drivers, the ones who sulk behind a marked police car,then speed off,and break all sorts of road rules when the coast is clear.
A serving police officer rang 2GB and said the number of unmarked was reduced to allow more marked cars to be seen, so as to give the impression of more police on the roads.
As I've written many times, triple the highway patrol and make all the new cars unmarked and catch the bad drivers.
For example, imagine how many drivers using mobil phones could be reminded of their dangerous behaviour.
Diligent,professional officers even with sensible discretion, would easily pay their way and when the ratbags are off the road ,they could revert to more general duties.