Tail lights are traditionally coloured red, so as to distinguish them from brake lights which are... oh, red. So. Red means stop. Therefore brake lights are appropriately coloured. Tail lights are to inform you that a car is there, and not braking. So, green would be more appropriate... on a busy motorway you'd look ahead and see a sea of green in good conditions, giving you the reassurance of a journey well planned. However, the colour change to red would be much clearer for great distances or in poor visibility, allowing you to take appropriate action.
Here in america, some indicators are simply flashing tail lights... so indicators: Red, brake lights: Red, tail lights: Red, madness.
The situation for the colour blind would remain unchanged.-- bs0u0155, Oct 30 2012 Red light night vision myth http://stlplaces.co...ht_vision_red_myth/ [spidermother, Oct 31 2012] Rogaining - the sport of applying a cream to your head? http://en.wikipedia.org/wiki/Rogaining [normzone, Nov 01 2012] *this really exists* http://www.igrowlas...jrrMCFY1DMgodmHMAzAIt's not even a real laser, just red LEDs. [DIYMatt, Nov 01 2012] Chromatic aberration in the eye http://lo.um.es/pan...ias/adjuntos/78.pdf [spidermother, Nov 02 2012] Rhodopsin http://en.wikipedia.org/wiki/Rhodopsin"Visual purple" [8th of 7, Nov 02 2012] I think the general idea is that you need to slow/stop as you approach either, whereas confusing green tail lights with a green traffic signal would be bad.-- MechE, Oct 30 2012 Too simple.
How about yellow for steady speed taillights, deepening to orange as you shed speed without braking, being green while you accelerate and red as you brake?
For an extra fee, you can choose your own color scheme, much like custom license plates. The rule against white light to the rear and strobes remains.-- normzone, Oct 30 2012 I'd propose sticking with red simply because it doesn't ruin your night vision when you're driving behind somebody.-- Alterother, Oct 30 2012 Like the idea, don't like the color choice.
I say red (for the nightvision as Alt said) to blue when you put on the brakes.
White in front, red in back that turns to blue when you brake. That seems to make the most sense.-- doctorremulac3, Oct 30 2012 //red ... night vision// (Link)-- spidermother, Oct 31 2012 //(link)// "It takes a while for true night vision to be recovered. About 10 minutes for 10%, 30-45 minutes for 80%, the rest may take hours, days, or a week."
Yeah, um, do you have a link to back up that link? If red light is really a myth (which is possible) then it must be the most widely believed myth in the history of ever, and I'm going to need at least a link to a .edu to confirm.-- DIYMatt, Oct 31 2012 Re:link, sorry, I'm not buying it. If you must use a light, a red light is the easiest on your nightvision. I'm going hillbilly on this one, so no amount of fancy science talk will sway me.-- Alterother, Oct 31 2012 There are plenty of astonishingly prevalent myths (or at least, erroneous oversimplifications) - Red-Green-Blue colour vision, the musical 'note', and separate regions on the tongue for sweet, salty, sour, and bitter, for example. People are just not that critical unless they make a deliberate effort. (Except for us Scorpios - we don't get sucked in by superstitious nonsense).-- spidermother, Oct 31 2012 Green is in the middle of the visible spectrum for humans, and would make sense, as it would shift to the blue as the vehicle is approached, but to the red if it was "getting away".-- 8th of 7, Oct 31 2012 Does two+ decades of tramping around in the woods and learning through experience that red flashlights are better for your night vision than white or green flashlights qualify as 'deliberate effort'? Sue me if I'm more inclined to believe years of personal experience than something somebody posted on the internet without citing supportive references.-- Alterother, Oct 31 2012 It's possible that it's the dimness, and the monochromaticity, rather than the redness per se. I once made and used a red LED torch for rogaining. It seemed to work well (little loss of night vision), but it may have been for the above reasons. I found that article confronting too, but it does seem technically correct as far as I can tell.-- spidermother, Oct 31 2012 In most city and motorway driving, I don't think night vision is a factor. In fact, if you can differentiate colour, you're not using your true night vision.
Light sensing technology is baked, on laptops and smartphones, simply tune the tail lights to maintain a certain intensity above ambient. All 'Night Vision' problems solved.-- bs0u0155, Nov 01 2012 Also, Blue, daft colour. What would the emergency services use?-- bs0u0155, Nov 01 2012 //It takes a while for true night vision to be recovered. About 10 minutes for 10%, 30-45 minutes for 80%, the rest may take hours, days, or a week.//
I think this rebuttal is somewhat undermined by citing a duration greater than 1 day as the period required for full recovery of "true night vision". In practice, any improvement in low-light vision over about 8 hours won't be a benefit to seeing at night (ignoring fairly stringent and specialised conditions, like wearing blackout patches from well before dawn to well after dusk for a week).-- Loris, Nov 01 2012 I originally liked the idea but I think both blue and green are a bit dodgy.
Lots of Green lights at a junction can be confusing Lots of Blue lights make it hard to spot the emergency services.
So the compulsory Yellow Flashing indicators as many vehicles already have when they brake heavily would be much clearer. Its like the whole motorway starts flashing ahead of you. I often hit the hazards when I am forced to brake rapidly on a motorway.-- PainOCommonSense, Nov 01 2012 "rogaining"...I had to look that one up. I thought you had a special flashlight for putting hair loss prevention medication on your head (link).-- normzone, Nov 01 2012 I'm not sure why lots of green tail lights at a junction would be any more confusing than lots of red lights at a junction... you can tell which ones the traffic lights are... few cars are mounted sideways on poles.-- bs0u0155, Nov 01 2012 //rogaining// that looks like fun. How does one get into this sport? Also, linky.-- DIYMatt, Nov 01 2012 // It's possible that it's the dimness, and the monochromaticity //
For your species, it's all about rhodopsin.
<link>
// I'm more inclined to believe years of personal experience than something somebody posted on the internet without citing supportive references. //
You're a strange one, for sure.-- 8th of 7, Nov 01 2012 //fun// It is. The pain only _really_ starts to settle in after the first 8 hours or so, which is handy. That's when, the second time, I thought, "Oh, *now* I remember why I decided never to do this again."
//// It's possible that it's the dimness, and the monochromaticity //
For your species, it's all about rhodopsin. //
The point is that dim light of any frequency won't destroy much rhodopsin, and that monochromatic light can give better clarity (obviously at the expense of colour rendering), partly because you eliminate chromatic aberration.-- spidermother, Nov 01 2012 So... if there's a red-to-green colour change involved with taillight-to-brakelight transition, won't it be using fresh, unbleached cells in the retina, and therefore convey more sensitivity?-- bs0u0155, Nov 01 2012 No, because (in the context of night vision) it's the rods that suffer from bleaching, not the cones. But (as someone said in an annotation that seems to have gone) you're not usually relying on true night vision while driving anyway. That's what headlights and street lights are for.-- spidermother, Nov 01 2012 //But (as someone said in an annotation that seems to have gone) you're not usually relying on true night vision while driving anyway.//
wait, I said that.. where's it gone? But yeah, if you can tell what colour the lights are.. it's not night vision. So indevidual colour fatigue applies, and colour-change gives increased sensitivity. Like having brighter lights... also your eyes are more sensitive to green than red or blue.-- bs0u0155, Nov 01 2012 In Vanuatu, all lights visible from the rear of the vehicle are required to be green. This includes reversing lights, and the interior lights of cars with rear windows.-- MaxwellBuchanan, Nov 01 2012 //chromatic aberration//
I was under the impression that the curvature of the retina eliminated chromatic aberration (apart from if you're wearing glasses, etc). I suppose different wavelengths still have different focal points, reducing your sharpness. 'Dispersion' is probably a better word for it though.-- mitxela, Nov 01 2012 The human eye does have chromatic aberration (which is, of course, caused by dispersion) (Link).-- spidermother, Nov 02 2012 Visible light is so restrictive. Why not ultra violet as an additional tail light?
The benefits would include the possibility of a tan whilst stuck in traffic, a weird glow from surrounding objects as well as attracting bees who would think the lights are flowers.
How about radio waves at the same time?
"We interrupt this programme to tell you that the car in front is slowing down"-- DenholmRicshaw, Nov 02 2012 Thinking about the junction, If I get one false positive and try to drive across a junction, straight into the car ahead who lets say has one faulty rear light. I think this this has to be more risk than slowing down when approaching a row of cars with red lights by thinking that this might be a red light.
Flashing orange is the way ahead.-- PainOCommonSense, Nov 02 2012 random, halfbakery