Do not fully understand your question but if you see a police car it is most likely controlling traffic. Weapons, any kind, are not a problem here. Normal avarage people do not have any kind of gun unless it is a hunting rifle or shotgun. Those are kept home not in your car. Pistols, revolvers etc are for target shooting and it is a hobby for some people. Still the gun stays home behind a locked door.
Following may be just my bad guess but if you go to a supermarket carrying a gun in your pocket AND for some reason someone sees it or you drop it THEN you are in trouble with the police. Big trouble.