This is the uniform of the JMPD:blue shirts, brown trousers, black leather boots and baseball caps sporting a JMPD badge.
Interestingly, if the officer is not in uniform you are not compelled to stop. This includes the hat. Your decision on how you'll use this - no hat, just drive on. Of course they'll make a huge noise about failing to obey instructions etc. etc. and off you'll go to court. You'll still end up with the talking on cell phone fine (or whatever your offence was) but the rest will be thrown out.
I, as a matter of principle ask anyone who asks me for my driver's license to show me their id document. Just smile and ask for it - it usually means that they have to go get it from their car or whatever.
This may sound silly or childish but in as much as they want me to behave responsibly on a road by being draconian, I want them to act like grown ups too and comply with the laws and regulations. Can you imagine if we had some drunken person who had just crashed into a crowd of school kids get off on a technicality because the person executing an arrest wasn't entitled to do so because they didn't have a cap on their bonce