Daytime Running Lights

[cbcdesign]

A white car fully visible with the sun behind it? Hmm not so certain about that....

leds are no better with the sun behind the white car. Leds are white too!

[jdrrco]

A white car fully visible with the sun behind it? Hmm not so certain about that....

leds are no better with the sun behind the white car. Leds are white too!

The reason lights are more effective at attracting attention than white paint is fairly easy to demonstrate. Take a piece of white paper and a torch into a room. Switch on the torch. The white paper is less visible than the torch, even when the torch isn't pointed directly at you.

Lights are devices that give off light, not just reflect it from some other source and are therefore more visible to the eye and from a greater distance than something painted white, even on the brightest sunny day.

This is also why traffic lights are lights and not just reflective discs with a light shining on them (like road signs). Light travels beyond the object, making it more visible from a greater distance.

[cbcdesign]

A white car fully visible with the sun behind it? Hmm not so certain about that....

leds are no better with the sun behind the white car. Leds are white too!

The reason lights are more effective at attracting attention than white paint is fairly easy to demonstrate. Take a piece of white paper and a torch into a room. Switch on the torch. The white paper is less visible than the torch, even when the torch isn't pointed directly at you.

Lights are devices that give off light, not just reflect it from some other source and are therefore more visible to the eye and from a greater distance than something painted white, even on the brightest sunny day.

This is also why traffic lights are lights and not just reflective discs with a light shining on them (like road signs). Light travels beyond the object, making it more visible from a greater distance.

Point a light meter at a white car on a sunny day then do the same at a row of LEDs. I guarantee the car gives a higher reading! Its a MUCH bigger object and therefore gives off more light, reflected or otherwise.

How visible the led lights will be is entirely dependant upon conditions and therefore the effectiveness of leds versus a white car body is nothing like as straight forward as you are suggesting.

[jdrrco]

A white car fully visible with the sun behind it? Hmm not so certain about that....

leds are no better with the sun behind the white car. Leds are white too!

The reason lights are more effective at attracting attention than white paint is fairly easy to demonstrate. Take a piece of white paper and a torch into a room. Switch on the torch. The white paper is less visible than the torch, even when the torch isn't pointed directly at you.

Lights are devices that give off light, not just reflect it from some other source and are therefore more visible to the eye and from a greater distance than something painted white, even on the brightest sunny day.

This is also why traffic lights are lights and not just reflective discs with a light shining on them (like road signs). Light travels beyond the object, making it more visible from a greater distance.

Point a light meter at a white car on a sunny day then do the same at a row of LEDs. I guarantee the car gives a higher reading! Its a MUCH bigger object and therefore gives off more light, reflected or otherwise.

How visible the led lights will be is entirely dependant upon conditions and therefore the effectiveness of leds versus a white car body is nothing like as straight forward as you are suggesting.

Nonsense! You are again talking about reflected light which depends on where the sun is in the sky, the angle of the object from which it is reflected and the off chance that the person glancing in that direction is correctly aligned to view the reflection. You don't seem to understand the basic principle of what light is!

Besides all of which, your proposed method of avoiding road accidents also depends entirely on everyone driving white cars and only on bright sunny days. Surely you can see the basic flaw in this theory?

[Mkuk0]

*gets popcorn and sits on sofa*

Anyone care to join me? This is gonna be fun :)

[cbcdesign]

A white car fully visible with the sun behind it? Hmm not so certain about that....

leds are no better with the sun behind the white car. Leds are white too!

The reason lights are more effective at attracting attention than white paint is fairly easy to demonstrate. Take a piece of white paper and a torch into a room. Switch on the torch. The white paper is less visible than the torch, even when the torch isn't pointed directly at you.

Lights are devices that give off light, not just reflect it from some other source and are therefore more visible to the eye and from a greater distance than something painted white, even on the brightest sunny day.

This is also why traffic lights are lights and not just reflective discs with a light shining on them (like road signs). Light travels beyond the object, making it more visible from a greater distance.

Point a light meter at a white car on a sunny day then do the same at a row of LEDs. I guarantee the car gives a higher reading! Its a MUCH bigger object and therefore gives off more light, reflected or otherwise.

How visible the led lights will be is entirely dependant upon conditions and therefore the effectiveness of leds versus a white car body is nothing like as straight forward as you are suggesting.

Nonsense! You are again talking about reflected light which depends on where the sun is in the sky, the angle of the object from which it is reflected and the off chance that the person glancing in that direction is correctly aligned to view the reflection. You don't seem to understand the basic principle of what light is!

Besides all of which, your proposed method of avoiding road accidents also depends entirely on everyone driving white cars and only on bright sunny days. Surely you can see the basic flaw in this theory?

Good greif! A light meters doesn't care if light is reflected or emmited, its still light and measures it accordingly. And you say I don't understand what light is? ******** Staggering!

Also, you have not even considered the narrow viewing angle that leds have compared to the numerous viewing angles a car body has due to panel shape! Furthermore the human eye has evolved to respond to light produced by the sun, i.e natural daylight, not leds which work over a far narrower spectrum.

As I said, get a light meter and conduct some proper tests rather than suggesting people mess around with torches and pieces of paper before you question my understanding of the properties of light! Its not as though the reflective properties of metal finished in a bright white high gloss finish is remotely similar to a sheet of paper!

I am not suggesting that DRL's are not useful in certain limited conditions however. I am talking about how useful they are in my case with my car which is bright white on a bright day and the answer is, not very! Obviously on a darker car they provide a bright source of light on an otherwise dark object, I never said otherwise did I?

[jdrrco]

A white car fully visible with the sun behind it? Hmm not so certain about that....

leds are no better with the sun behind the white car. Leds are white too!

The reason lights are more effective at attracting attention than white paint is fairly easy to demonstrate. Take a piece of white paper and a torch into a room. Switch on the torch. The white paper is less visible than the torch, even when the torch isn't pointed directly at you.

Lights are devices that give off light, not just reflect it from some other source and are therefore more visible to the eye and from a greater distance than something painted white, even on the brightest sunny day.

This is also why traffic lights are lights and not just reflective discs with a light shining on them (like road signs). Light travels beyond the object, making it more visible from a greater distance.

Point a light meter at a white car on a sunny day then do the same at a row of LEDs. I guarantee the car gives a higher reading! Its a MUCH bigger object and therefore gives off more light, reflected or otherwise.

How visible the led lights will be is entirely dependant upon conditions and therefore the effectiveness of leds versus a white car body is nothing like as straight forward as you are suggesting.

Nonsense! You are again talking about reflected light which depends on where the sun is in the sky, the angle of the object from which it is reflected and the off chance that the person glancing in that direction is correctly aligned to view the reflection. You don't seem to understand the basic principle of what light is!

Besides all of which, your proposed method of avoiding road accidents also depends entirely on everyone driving white cars and only on bright sunny days. Surely you can see the basic flaw in this theory?

Good greif! A light meters doesn't care if light is reflected or emmited, its still light and measures it accordingly. And you say I don't understand what light is? ******** Staggering!

Also, you have not even considered the narrow viewing angle that leds have compared to the numerous viewing angles a car body has due to panel shape!

As I said, get a light meter and conduct some proper tests before you question my understanding of the properties of light!

I am not suggesting that DRL's are not useful in certain limited conditions. I am talking about how useful they are in my case with my car which is bright white and the answer is, not very!

No, a projected light makes no difference to how visible a car is - how silly of me! In your case, where you only ever drive your bright white, always immaculately clean car just on perfectly sunny days, it would make no difference at all. You obviously know far more than any of us physicists or indeed all the car safety experts employed by governments and car manufacturers. I bow to your vastly superior knowledge!

Now all you need to do is get all other road users and pedestrians to carry a light meter and job done!

Presumably you're an amateur photographer which is why you keep banging on about light meters, have you not heard of a flashgun? Amazing they ever caught on really when all that photographers need to do is drive a white car in front of their subjects, that would be a much better idea.

I shall say no more on the subject, clearly no point in the presence of such an expert.

What a shame this sort of rubbish hijacks a simple question about whether the DRL LEDs fitted on the Prius can be activated or not.

[cbcdesign]

A white car fully visible with the sun behind it? Hmm not so certain about that....

leds are no better with the sun behind the white car. Leds are white too!

The reason lights are more effective at attracting attention than white paint is fairly easy to demonstrate. Take a piece of white paper and a torch into a room. Switch on the torch. The white paper is less visible than the torch, even when the torch isn't pointed directly at you.

Lights are devices that give off light, not just reflect it from some other source and are therefore more visible to the eye and from a greater distance than something painted white, even on the brightest sunny day.

This is also why traffic lights are lights and not just reflective discs with a light shining on them (like road signs). Light travels beyond the object, making it more visible from a greater distance.

Point a light meter at a white car on a sunny day then do the same at a row of LEDs. I guarantee the car gives a higher reading! Its a MUCH bigger object and therefore gives off more light, reflected or otherwise.

How visible the led lights will be is entirely dependant upon conditions and therefore the effectiveness of leds versus a white car body is nothing like as straight forward as you are suggesting.

Nonsense! You are again talking about reflected light which depends on where the sun is in the sky, the angle of the object from which it is reflected and the off chance that the person glancing in that direction is correctly aligned to view the reflection. You don't seem to understand the basic principle of what light is!

Besides all of which, your proposed method of avoiding road accidents also depends entirely on everyone driving white cars and only on bright sunny days. Surely you can see the basic flaw in this theory?

Good greif! A light meters doesn't care if light is reflected or emmited, its still light and measures it accordingly. And you say I don't understand what light is? ******** Staggering!

Also, you have not even considered the narrow viewing angle that leds have compared to the numerous viewing angles a car body has due to panel shape!

As I said, get a light meter and conduct some proper tests before you question my understanding of the properties of light!

I am not suggesting that DRL's are not useful in certain limited conditions. I am talking about how useful they are in my case with my car which is bright white and the answer is, not very!

No, a projected light makes no difference to how visible a car is - how silly of me! In your case, where you only ever drive your bright white, always immaculately clean car just on perfectly sunny days, it would make no difference at all. You obviously know far more than any of us physicists or indeed all the car safety experts employed by governments and car manufacturers. I bow to your vastly superior knowledge!

Presumably you're an amateur photographer which is why you keep banging on about light meters, have you not heard of a flashgun? Amazing they ever caught on really when all that photographers need to do is drive a white car in front of their subjects, that would be a much better idea.

I shall say no more on the subject, clearly no point in the presence of such an expert.

What a shame this sort of rubbish hijacks a simple question about whether the DRL LEDs fitted on the Prius can be activated or not.

You mean the same safety experts who advised governments and car manufacturers that HID lamps improved road safety when many real world road users find them to be overly bright at best and downright dangerous at worst?

A projected beam from an LED light is very effective head on or at certain narrow angles certainly but many would agree that white leds on a white car on a bright day in some circumstances are going to be ineffective, that is the point I am making.

If I had a black car which vehicle colour studies have shown has the lowest safety record of all compared to white cars which have the highest, I may think differently of course!

By all means continue to refute any weaknesses whatsoever in the safety DRL's provide on white cars. Many would disagree with you!

[Cyker]

Hate DRLs. They look stupid, are highly distracting and will probably cause accidents involving motor and pedal cyclists to rise, since DRLs are actually USEFUL on them but will now be drowned out by flood of stupid and overly bright car DRL's. :censor: