In what might be referred as ‘the good old days’ (and by that I mean only a few years ago), it was fairly easy to identify which of the services a vehicle belonged to simply by looking at the colour of the beacons attached to it. Police, fire, and ambulances generally had blue lights; doctors had green, the police seemed to get alternating red at some point. There could also be yellow, on working vehicles that could be a hazard, such as slow-moving refuse lorries, tow-trucks, and various road maintenance vehicles.
While many still sport the common incandescent light fittings, with coloured lenses which convert the white light from the conventional bulb behind, newer fitting are manufactured using LEDs, which do no usually have tinted lenses or covers.
Unlike the white light produced by a filament bulb, which requires a coloured lens, filter, or coating to produce the desired output colour, the light from an LED is created within the device, so no filter is needed, and the devices generally come with clear lenses, which maximises their output. (For the pedantic, I’m calling white a colour, although it is made up of many, and also not going to refer to the various light conversions that take place within the structure of various visible light LEDs.)
The end result is that it’s no longer easy to tell what service an unmarked vehicle belongs to just by looking at the auxiliary lights. All you see when they are not energised is a clear fitting, and the colour only becomes apparent when they are activated.
Case in point was the Audi I tripped over recently. Roof mounted light bar, but… transparent housing.
I couldn’t see any markings or other equipment(eg radio) fitted to it, or lying on the seats, nor anything screwed to the bodywork. There were no cameras mounted anywhere, nor a second rear-view mirror.
The same anonymity was true of the driver, inside the adjacent ‘greasy spoon’ and collecting a large bag of goodies to help him survive the rest of the day. Dressed in black, he did have any kit, or badges apparent.
There were no lights in the rear window (not even pop-up types), but I spotted a dash-mounted temporary unit, probably blue/red, and a look at the front suggests a small pair of non-Audi ‘white’ squares in the lower grille, which I suspect are LEDs.
Black Audi with LEDs
FYI – Unmarked police cars around here look more like this when at work: