In the old days, many police stations were furnished with blue lanterns, mounted on the outside wall next to the door, to guide those seeking emergency assistance after dark. These were probably gas lamps originally, with blue glass panes, and the idea carried over into the electric age (mostly in the name of tradition) with all sorts of lamp designs. The shape is less important to me than the color of the light emitted, and no need for a "police" text element, although some lamps certainly have that. Sorry - I'm currently unable to provide an example photo, but I think it's fairly straightforward: as long as it can go on a wall, and put out a decent strength of blue light, I'll take it.

A second-best option would be pole-mounted, like those lamps that can be put on fence posts and such. Thanks!

P.S. - I realize that there is a blue police-badge-shape neon light out there somewhere... but I'm looking for a more traditional lamp.

I thought that sounded interesting enough to look up, so seeing that I was there anyway, have a picture.

Yeah, that's a nice example.

Some - even in the Victorian era - were just round globes, sometimes two white ones with a blue in the middle. In New York, they sometimes had green ones - maybe because of the high percentage of Irish cops on the force? Just a theory. Here in Chicago, a lot of the cop shops are more modern-looking these days, but fire stations still have red and green lights beside the truck doors (the fire trucks also have red and green, like ships or airplanes). I tried just now to get my image site to upload some photos, but no dice. So thanks, Charity, for the photo.