UK cop car lights

[co911]

Do police cars in the UK have red and blue, or just blue lights?

[ChrisF202]

From what ive seen, most European countries use blue. Asia (like China, the Korea's, Japan, etc) use red or red/blue. Africa, I have no clue. Latin America I belive is red/blue. I havent really seen pics of very many cop cars from outside the US, Canada, Australia, Europe, etc

[Sgt Lobster]

Police vehicles in the UK and for that matter those used by the fire & ambulance services have blue flashing lights. Many emergency vehicles however are capable of showing flashing red lights to the rear - hopefully stops you getting rear ended! Flashing amber lights are used by break down trucks, council vehicles and the like; and doctors can use flashing green lights on their vehicles if being used in an emergency.



Lobster.

[Cockney Corner]

... hence the expression "Blues & Twos" over here (meaning blue lights and two tone siren are on) for stops.

[co911]

Sarge, can I aks why the Uk hasn't gone to red and blues?

[Sgt Lobster]

Co911,

I'm not sure that there is a problem with blue lights on their own?

It is also illegal in the UK to show red lights other than to the rear of a vehicle.


Lobster.:)

[JohnKelly]

To the best of my knowledge, Emergency Services in Australian use Blue and Red.

I haven't been to all Australian States, so that is why I can't be 100% sure.

The reason that the twin colours of Blue and Red were adopted in lieu of the single colour was that one colour can be seen better in daylight and the other can be seen better at night, so both combined covers both situations.

JohnKelly
Australia

[co911]

Sarge many US depts have blue lights only, particulary in New England and on the East Coast. The problem I guess is that blue is a very difficult color to see during the day. Red is far easier to see, hence its use on tail/brake lights. I once read that amber is the most visible color of all whether by day or night.

[ChrisF202]

I think blue is much easier to see then red, day or night.

[Sgt Lobster]

I've always found blue lights to be fine day or night. As stated most of our cars can show flashing red lights to the rear.

Lobster.

[silentbob]

If you want to get into the nitty gritty....

Green is the most visible as it is in the center of the visible spectrum (for humans) hence the huge proportion of green neon lights on businesses from the 'neon era'. Between that and the arguments of naturally occurring colors referenced below lead to the use of emergency green for many fire/ems vehicles.

Red and violet, being on the ends of the spectrum, are more likely to be missed by people who have poor color vision.

Green was already in use as 'go' before a lot of this was hashed out. Many people have a hard time differentiating between hues of blue and green (teal green is seen as blue by a huge portion of the population).

Red, being quite opposite and not easily confused for green is a natural option. Red was also one of the easiest colors of lights to produce before the last 40 years of technological improvements. With the advent of affordable LED technology you will notice a huge increase in visibility of blue lights. They also remain blue without the washing out that halogen lighting experiences.

Reds and greens are frequently found in nature though so background interference is a concern.

I have yet to read any conclusive studies of the visibility of the new generation 'true blue' LED lights but from my personal perspective they are the most effective light out there. They are not on the fringe of the visible spectrum and they are not a color found often in nature. Add the quick on/off cycle as opposed to fading on and off of a tradional light and the multiple/random flashing patterns and you have a whole new ballgame.

Part trivia, part personal opinion.

[Sleuth]

Silentbob, where did you get this information? I had always understood that the colors most visable were white, then amber, not green.
And since we are talking about a light source, how much of that color appears in nature (as reflected light) seems irrelevant. Neon lights were colored using neon gasses, and I don't recall a preponderance of green. I do recall that some colors were cheaper than others.

I do recall seeing the strobe lights of a NH State Trooper being reflected by the leaves in the trees, before I rounded the bend and saw the car. So factors of intensity, focus, and duration of the flash, also enter into visability.

[silentbob]

My post was an overview of research and technology as utilized by many industries but most valuable to the advertising industry. I spent ten years working in technical visual fields mostly including the technical side of the photographic industry. The visual industries (ie predominantly advertising) have spent considerable time and money figuring out that there are three things that effect the way a colored item is perceived.

a) position in the visible color spectrum (my references to color blindness and persons with limited color perception)

b) confusion with background color (my references to color in nature - a red light in front of a field of red tulips is much less effective than a red light in front of a field of yellow daffodils)

c) the technological ability to produce the proper color (in print media it is the limitations of inks and papers, in photographic works it the limits of photo sensitive papers and films)

My post was about the effectiveness of color in general and the roles that it plays. Yes, intensity and duration are involved in that but since $ drives research and most advertising is not time/duration sensitive the amount of studies and research is much more limited.

Part C is usually the biggest challenge and the reason we make many of our choices and observations.

You are right... White is always the brightest because you are not filtering out any of the visible spectrum. Red and Blue are 'pure' colors which require the most filtering of the spectrum and, thereby, the most reduction in intensity from a white lightsource. Amber, not yellow, is more of a range of color or, technically, a wider swath of the spectrum. This all adds up to more intensity, less filtration.

I am sorry if my post strayed too far from the post but sometimes having an understanding of why makes it easier to solve problems.

[crashman]

Yes

All Australian States have red and Blue Emergency lights and the reasons are as discussed before, the ability to see the different colours at different times of the day. Also to ensure all vehicles give way to all emergency vehicles and not just pull over fo the police.

Though now the public is just ticking off the fire truck drivers and ambulance drivers, because the first reaction of a member of the public to hearing a siren and seeing the flashing red/blue is to hit the brakes and check their speedo to make sure they are not speeding. Little do they realise that the emergency vehicle is closing in on them at a great rate of knots with the intent of getting past and onto their emergency, only to have the idiot in front brake and slow down. :rolleyes:

[Sleuth]

Crashman, as an investigator for the Federal Government, I always drove unmarked cars, with concealed red/blue lights and siren. We quickly learned that the fastest way to get from A to B was put a light on the dash, but leave everything turned off. If we went more than 20 MPH faster than traffic, you could treat them like stationary objects.
If we saw a local/state police car, we would turn on the lights & siren until we past them, and go back to stealth mode. Worked for me!

[ChrisF202]

Originally posted by Sleuth
Crashman, as an investigator for the Federal Government, I always drove unmarked cars, with concealed red/blue lights and siren. We quickly learned that the fastest way to get from A to B was put a light on the dash, but leave everything turned off. If we went more than 20 MPH faster than traffic, you could treat them like stationary objects.
If we saw a local/state police car, we would turn on the lights & siren until we past them, and go back to stealth mode. Worked for me!
Dont all federal agencies in the US use red/blue lights?

[Sleuth]

In general, they try to comply with state laws. The problem arises when you are stationed in one state, but work in others. When I was stationed in Boston, I covered Conn., Mass., Southern N.H. & Vermont, and a bit of Maine.