What is the point of flashing lights?

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Bustacapp
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What is the point of flashing lights?

Postby Bustacapp » Fri Oct 05, 2012 12:06 pm

I've never understood why cycling lights flash. I always think they are far less visible than a nice, bright and solid 'always on' light. I saw a guy battling through the bleak morning darkness this morning with a constant light on and it was so much easier to spot from the cosy warmth of my car.

Is it to save battery power or what?

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adr82
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Re: What is the point of flashing lights?

Postby adr82 » Fri Oct 05, 2012 12:12 pm

I find the opposite is true. They stand out from most of the other lights you will see which are all solid - traffic lights, vehicle lights, streetlights, building lights, etc. If they weren't highly visible then emergency vehicles wouldn't use them! Anyway every light I've ever bought (even a tiny cheap one) has had both solid and flashing modes, so it's not like you can't pick and choose if you want.
Last edited by adr82 on Fri Oct 05, 2012 12:13 pm, edited 1 time in total.

TakeTurns
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Re: What is the point of flashing lights?

Postby TakeTurns » Fri Oct 05, 2012 12:13 pm

Constant light should be used to lighten up the road ahead for pot holes etc. A flashing light is mainly used to gain the attention of others as it is more alerting. Due to cyclists being vulnerable road users.

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Bustacapp
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Re: What is the point of flashing lights?

Postby Bustacapp » Fri Oct 05, 2012 12:20 pm

adr82 wrote:I find the opposite is true. They stand out from most of the other lights you will see which are all solid - traffic lights, vehicle lights, streetlights, building lights, etc.



I don't see how the light being in 50% darkness can help visibility. And I don't understand with the light not being distinguishable from other solid lights, as long as you see a light then you know there is an obstacle to avoid!!

adr82 wrote:If they weren't highly visible then emergency vehicles wouldn't use them!


If you could get a bike light that can perfrom like this then I agree:

Image

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Pross
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Re: What is the point of flashing lights?

Postby Pross » Fri Oct 05, 2012 12:23 pm

TakeTurns wrote:Constant light should be used to lighten up the road ahead for pot holes etc. A flashing light is mainly used to gain the attention of others as it is more alerting. Due to cyclists being vulnerable road users.


This. Anything moving catches the attention more. I have 3 rear lights one on constant and the other two on different flash modes. Front I have a light to light unlit country lanes and another on flash for catching attention. It does also help that flash mode extends battery life but that's not the main reason. Reflective bands on the ankles are also very good at catching a driver's attention.

Richard Farrant
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Re: What is the point of flashing lights?

Postby Richard Farrant » Fri Oct 05, 2012 12:29 pm

I thought the Highway code says that you have to have a solid light on the rear?

King Jeffers
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Re: What is the point of flashing lights?

Postby King Jeffers » Fri Oct 05, 2012 12:32 pm

I normally have a solid on the rear ( :oops: ) + a flasher... Usually a just a cheapo knog light.

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Pross
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Re: What is the point of flashing lights?

Postby Pross » Fri Oct 05, 2012 12:33 pm

Richard Farrant wrote:I thought the Highway code says that you have to have a solid light on the rear?



Nope

The Highway Code wrote:60
At night your cycle MUST have white front and red rear lights lit. It MUST also be fitted with a red rear reflector (and amber pedal reflectors, if manufactured after 1/10/85). White front reflectors and spoke reflectors will also help you to be seen. Flashing lights are permitted but it is recommended that cyclists who are riding in areas without street lighting use a steady front lamp.


Of those it is the reflectors (particularly the pedal reflectors) that most cyclists, including me, don't adhere to. The pedals are a bit of an issue with clipless but I'm hoping to get some orange reflective tape that I can stick onto them and the back of my shoes.

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CiB
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Re: What is the point of flashing lights?

Postby CiB » Fri Oct 05, 2012 12:36 pm

Bustacapp wrote:I don't see how the light being in 50% darkness can help visibility. And I don't understand with the light not being distinguishable from other solid lights, as long as you see a light then you know there is an obstacle to avoid!!

But you know that's wrong. Put two lights one flashing and one solid in a busy visual environment and the flashing one will attract your attention. It's not the quantity of the light, it's the intermittent nature that makes it more visible. Being off for lord knows how many hundredths of a second doesn't make it not a light.

And like others have said, you use both anyway. Flashing so that the numpty half-asleep drivers might spot you, and fixed because it's what the HC requires and is also visible. I have three at each end, 2 solid 1 flashing. Sometimes the other way round on the back.

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adr82
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Re: What is the point of flashing lights?

Postby adr82 » Fri Oct 05, 2012 12:47 pm

Bustacapp wrote:I don't see how the light being in 50% darkness can help visibility. And I don't understand with the light not being distinguishable from other solid lights, as long as you see a light then you know there is an obstacle to avoid!!

It's not like it's dark for 5 seconds! The lights I use flash several times a second, you're not going to miss it even if you just do a quick glance in its direction.

CiB wrote:
Bustacapp wrote:I don't see how the light being in 50% darkness can help visibility. And I don't understand with the light not being distinguishable from other solid lights, as long as you see a light then you know there is an obstacle to avoid!!

But you know that's wrong. Put two lights one flashing and one solid in a busy visual environment and the flashing one will attract your attention. It's not the quantity of the light, it's the intermittent nature that makes it more visible. Being off for lord knows how many hundredths of a second doesn't make it not a light.

Exactly. Human eyesight is drawn to change/movement in the surrounding environment, so you'd expect that a flashing light would be noticed faster than a solid one. Don't know if anyone has actually done any research to verify this though. In my own experience I find it far easier to pick out a single relatively dim flashing light on a busy street compared to a solid light in a similar situation.

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Re: What is the point of flashing lights?

Postby Mr Will » Fri Oct 05, 2012 13:25 pm

As others have said - sudden changes instinctively draw your eye making a flashing light easier to notice, if not necessarily easier to see.

Flashing is particularly helpful in the presence of lots of other lights - a solid bike light that would be bright and easy to spot on a country lane will blend in dangerously on a wet city street surrounded by traffic; that's where a flashing light comes in to it's own.
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Pross
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Re: What is the point of flashing lights?

Postby Pross » Fri Oct 05, 2012 13:40 pm

When I use my main front light on flash in an urban environment all the reflective street lights start flashing and you see drivers (and pedestrians) looking about to work out where it is coming from which to me shows it is doing its job.

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bompington
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Re: What is the point of flashing lights?

Postby bompington » Fri Oct 05, 2012 14:02 pm

Plenty of quality flashing and fixed lights to choose from here

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Bluedoggy
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Re: What is the point of flashing lights?

Postby Bluedoggy » Fri Oct 05, 2012 15:13 pm

I use a Exposure Maxx D on Flash slightly dipped so not to blind. I definatley get noticed.....
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Peddle Up!
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Re: What is the point of flashing lights?

Postby Peddle Up! » Fri Oct 05, 2012 15:30 pm

Mr Will wrote:Flashing is particularly helpful in the presence of lots of other lights - a solid bike light that would be bright and easy to spot on a country lane will blend in dangerously on a wet city street surrounded by traffic; that's where a flashing light comes in to it's own.



The best argument.
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Wrath Rob
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Re: What is the point of flashing lights?

Postby Wrath Rob » Fri Oct 05, 2012 15:59 pm

Solid light to see.
Flashing light to be seen.
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Simon Masterson
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Re: What is the point of flashing lights?

Postby Simon Masterson » Fri Oct 05, 2012 16:16 pm

adr82 wrote:I find the opposite is true. They stand out from most of the other lights you will see which are all solid - traffic lights, vehicle lights, streetlights, building lights, etc. If they weren't highly visible then emergency vehicles wouldn't use them! Anyway every light I've ever bought (even a tiny cheap one) has had both solid and flashing modes, so it's not like you can't pick and choose if you want.


This!

My first LED light had flashing modes, but that was before they were technically legal. I always use a flashing mode on my rear light for the reason given above; never on my front light however. I understand why some people do but I use it to see with!

The one and only gripe I have ever had with flashing modes is that they usually have non-mechanical switches. That first light I had - best part of a decade ago I would think; it broke about this time last year - was very cheap and suffered from the old problem of battery movement. If the battery shifted despite whatever I'd put in there to attempt to stop it, the light would go out (which resulted in one or two near misses!); my trusty Cateye HL500 (which still works but is in retirement!) having a mechanical switch would just switch back on with a good whack!

CubeMark
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Re: What is the point of flashing lights?

Postby CubeMark » Fri Oct 05, 2012 18:25 pm

Why do car indicators flash? Same reason. To be seen.

JamesEs
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Re: What is the point of flashing lights?

Postby JamesEs » Fri Oct 05, 2012 19:03 pm

Wrath Rob wrote:Solid light to see.
Flashing light to be seen.


This

geebus
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Re: What is the point of flashing lights?

Postby geebus » Sat Oct 06, 2012 06:45 am

I can't find the image I was looking for, but it was a 'better' (bike more hidden) idea along the lines of this:
Image
(In the picture I was thinking of the bike in front was lined up with the headlights behind fairly well from the viewpoint of the picture and at a glance you would expect there to be two vehicles there with a more vulnerable one in front.)

With daylight running lights motorcycles and of course pedal cycles can easily be hidden in a haze of other single-point light sources out there.
Even worse at night.
A flashing light makes it significantly more noticeable as these aren't used on motor-vehicles apart from for turn signals.


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