Give PO's access to more roleplay vehicles (ie. Hemmnt Flatbed (for towing vehicles maybe), Jeeps, police go-carts, maybe a darter for scouting)
Maybe give PO's access to bait vehicles, I personally don't understand why that's only for higher ranks...
Gun wise, it's understandable that PO's have shite guns because its only the second APD rank, maybe add 9mm supp, or a sawed off kozlice taser?
I think to many it's not abundantly obvious that there is such a thing as balance. A PO should simply not be able to have access to a MK1 or a Promet MR, that would kill the server. But there are some things you could do to increase popularity of the cop role...