Do flashing front lights induce fits?

[TwickenhamCyclist]

Agree with the rest of it, but what is the average flash rate, does anyone know?

In a highly scientific experiment I started a 5 second countdown on my phone and counted 15-20 flashes in that period from my bike lights or about 4/5 FPS. 15-30 FPS is a very high flash rate, I mean PAL TV is 'only' at 30 FPS.

Dough - I wanted to say bike lights were a lot slower than than that! Sorry

 

[Little yellow Brompton]

Would you like the short version of why he's walking bollocks, or the long version?

 

[Zoiders]

I do recall a story from France where they removed the tress from the central reservation of a divided dual carriage way as the interval at which they had been planted had set off a few photo sensitive drivers.

 

[Night Train]

I find flashing LED lights problematic, it gives me headaches sometimes. I found this when I was playing with one of my light sets. It was mainly the red one that was the problem and so I only use steady lighting on my bikes. At a distance it isn't really a problem except when trying to judge distance and movement.

I find LED rear lights on cars quite difficult when I am driving at night. As I scan the view ahead I find the red lights seem to flicker and track across my range of vision as I look around. In heavy traffic I have to look ahead keeping my head and eyes fairly still and blink when I move my head or eyes to look around.

 

[briantrumpet]

Yes, a car driver told me that my rear light was too bright once and to turn it off.

And I had a passenger (in a car that had just overtaken me and then slowed down to less than my previous speed) lean out and tell me to turn off my flashing light (all of 1 watt of it) as it was 'blinding' the driver. I was quite pleased that, for once, a driver had seen me.

 

[BentMikey]

Dough - I wanted to say bike lights were a lot slower than than that! Sorry

Well, sort of both. AFAIK LED lights are controlled to less than maximum intensity by flashing them very fast, which is why sometimes you'll see bus LED lights flashing on youtube videos. They appear to be on constantly to the eye, but flash on video as the flashes go in and out of phase with the video framerate. The much slower flashing of flashing mode bike lights is done for visibility purposes, and should be well below the epilepsy tolerance point.

 

[GFamily]

I was once asked to turn my flashing red rear light off before I wheeled my bike onto a station platform. The reason given was that some trains have flashing red rear lights, and train drivers are taught to stop in a hurry if they see such lights first and worry about whether it could be a bicycle on the platform afterwards. Which I think is logical enough and so I always try and remember to turn my lights off before I get to the platform. I have to add that I don't always remember to do this and I only remember being asked to turn the lights off once...

As I understand it, it's any moving red light on the platform that constitutes a STOP signal to trains.

I've been asked to hide the standlight on my Brompton at Oxford Road station. Fortunately I've now sacked the dynamo set-up and replaced it with AAA Led lights.

 

[Little yellow Brompton]

I was once asked to turn my flashing red rear light off before I wheeled my bike onto a station platform. The reason given was that some trains have flashing red rear lights, and train drivers are taught to stop in a hurry if they see such lights first and worry about whether it could be a bicycle on the platform afterwards. Which I think is logical enough and so I always try and remember to turn my lights off before I get to the platform.

It might be logical, but it's based on a false premise. Trains DO NOT have flashing red lights, and the manual signal to stop a train is not a flashing red light or even a waved red petticoat, but a steadt red light moved vertically through an arc of 60 degrees. Nothing at all like a flashing red light at knee/waist level. I used to have a buffoon at my local station who would chase cyclsits down the platform citing "elf un safee" to get them to turn off lights . A written complaint to Arriva finally shut him up.

 

[Night Train]

Well, sort of both. AFAIK LED lights are controlled to less than maximum intensity by flashing them very fast, which is why sometimes you'll see bus LED lights flashing on youtube videos. They appear to be on constantly to the eye, but flash on video as the flashes go in and out of phase with the video framerate. The much slower flashing of flashing mode bike lights is done for visibility purposes, and should be well below the epilepsy tolerance point.

Ahhh, maybe that is why I see LED lights on cars flicker and track.
Do you have a source for this bit of info at all?

 

[classic33]

photosensitive epilepsy http://www.epilepsy....ilepsy/triggers

Bit about strobe lights and red flashing cycle lights!

Can epileptics ride bikes? Maybe he meant them as well as peds.

They always warn about flash photography on news reports don't they!


I don't have epilepsy but I find flashing bright lights on country roads with no other lighting are distracting and nauseating!

Yes & as a person who suffers from/with the condition can I ask why shouldn't I?

As for the flash rate, a CRT screen refreshes at the lower end of the scale. Warned that I shouldn't work with computers for a living. I did do.

For me this warning of flash photography/flashing images comes down more on the side of being over cautious, just in case. Kind of like the warning printed on some bags of nuts a few years ago about traces of nut may be evident.

Take the artificial light out of it, replace it with the sun & a set of railings down the side of the road, with the sun coming through the railings. The same effect can be achieved in daylight.

 

[semislickstick]

Yes & as a person who suffers from/with the condition can I ask why shouldn't I?

As for the flash rate, a CRT screen refreshes at the lower end of the scale. Warned that I shouldn't work with computers for a living. I did do.

For me this warning of flash photography/flashing images comes down more on the side of being over cautious, just in case. Kind of like the warning printed on some bags of nuts a few years ago about traces of nut may be evident.

Take the artificial light out of it, replace it with the sun & a set of railings down the side of the road, with the sun coming through the railings. The same effect can be achieved in daylight.

Absolutely you should! You have photo-sensitive epilepsy? I assumed the concerned person meant fellow photo sensitive epileptic walkers and cyclists might have a problem, not drivers, who, I believe have to have a medical & prove a fit free time period?

 

[Davidc]

Told the last idiot that told me my rear flashing light was illegal and too bright that they were now compulsory (I know it's a lie BTW) and that all bikes had to have lights 20 times brighter by the end of next month.

Worryingly he seemed to believe me - said he'd be writing to his MP to complain.

The flashing speed is slow enough that AFAIK it shouldn't affect epileptics but I'd listen to informed advice.

I find I'm seen and avoided better with one constant plus one flashing at each end. The brighter the better, and day and night.

 

[classic33]

Absolutely you should! You have photo-sensitive epilepsy? I assumed the concerned person meant fellow photo sensitive epileptic walkers and cyclists might have a problem, not drivers, who, I believe have to have a medical & prove a fit free time period?

Both the cause & trigger are unknown, in my case. It may be one thing it may be another.

However to try & answer the question asked(its come up before) I did ask a specialist at the hospital, showing him the types of lights I was talking about & he had never heard of a fit being caused by flashing bike lights.

See
http://www.epilepsyontario.org/clie...2571fc0047e3d3?OpenDocument&Highlight=2,flash

 

[buggi]

i'm not a medical person but i don't think so for two reasons.

1. i think it has to be flashing quite fast, like strobe lighting, to have that sort of effect.
2. if they did, they would have been banned by now.

so therefore it's total bollox.

 

[classic33]

i'm not a medical person but i don't think so for two reasons.

1. i think it has to be flashing quite fast, like strobe lighting, to have that sort of effect.
2. if they did, they would have been banned by now.

so therefore it's total bollox.

The link given gives a frequency of 5 times a second, 5 hertz.