Is a flashing rear light during the day a good idea?

Commuting, Day rides, Audax, Incidents, etc.
ossie
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Re: Is a flashing rear light during the day a good idea?

Post by ossie »

Psamathe wrote: 27 Sep 2021, 4:52pm But on quite bendy country roads where you might be the only cyclist around might they be more effective to highlight your presence to a less attentive driver (I appreciate that responsibility is on drivers to be fully attentive and it's not the responsibility of cyclists to make-up for drivers with their thoughts far away from driving - but they do exist and I'd rather not be the individual who suffers the outcome of such a driver ...).
Ian
It's the main reason I've started using them, however more for being seen when entering areas under tree canopies on bright days. I'll try and demonstrate with a street view on one of my rides, which are mostly rural.

https://www.google.co.uk/maps/@50.82910 ... 312!8i6656

When entering this on a sunny day from either end it's like entering a tunnel. As a motorist or cyclist you are looking at a wall of darkness on approach. You just cannot see cyclists unless they have DRL's. You may see a silhouette. It certainly makes me feel less vulnerable.

Recently my elderly father in law ran into the back of a car that had stopped under a canopy of trees on a sunny day. I viewed the dashcam footage, he had five seconds to react but just didn't see it. In his words 'it all went black'. You could argue he shouldn't be on a road but as a cyclist we have no choice in who's driving, who's wearing poundland sunglasses etc.

This is a sad case and may well have been discussed on here. Driver who hit and killed cyclist said victim "seemed the same colour as the shadows"

https://road.cc/content/news/198371-dri ... ore_news=1

Notwithstanding the onus is fully on the motorist to drive to the conditions, I just wonder if this cyclist had a bright rear light it would have differentiated them from the shadows to a driver who clearly wasn't paying proper attention. The coroner Indicated the trees and clothing were factors in the collision, I'm not saying I agree with his assertions as I said the onus should be on the motorist to drive to the conditions but we all know that doesn't happen.
toontra
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Joined: 21 Dec 2007, 11:01am
Location: London

Re: Is a flashing rear light during the day a good idea?

Post by toontra »

ossie wrote: 29 Sep 2021, 3:44pm It's the main reason I've started using them, however more for being seen when entering areas under tree canopies on bright days.
That's certainly one of the times I feel they help most. Also (riding in the east coast of Scotland) when the dreaded sea mists descend and visibility is sometimes reduced to under 50 yards, even on otherwise sunny days.
bjlabuk
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Re: Is a flashing rear light during the day a good idea?

Post by bjlabuk »

Ah the haar ! Yes north east scotland at its best. And when there isn't a haar, you are riding into a strong headwind no matter what direction you are travelling, or it is pxssing with rain! I was out on a new route today taking in the South Deeside Road. Front and rear flashing LED lights and high vis jacket. Decided to take the primary position for most of the ride and found it worked! That has certainly given me confidence as normally I ride in the secondary position.
xerxes
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Joined: 10 May 2013, 7:22pm

Re: Is a flashing rear light during the day a good idea?

Post by xerxes »

There's more than enough light pollution without adding to it unnecessarily. Unfortunately, many cars now have 'running lights' which are switched on by default.
philvantwo
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Joined: 8 Dec 2012, 6:08pm

Re: Is a flashing rear light during the day a good idea?

Post by philvantwo »

xerxes wrote: 30 Sep 2021, 4:20pm There's more than enough light pollution without adding to it unnecessarily. Unfortunately, many cars now have 'running lights' which are switched on by default.
Light pollution??
Bmblbzzz
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Re: Is a flashing rear light during the day a good idea?

Post by Bmblbzzz »

simonineaston wrote: 25 Sep 2021, 8:01pm Agree no advantage to daylight lights, at all. Recall too that research indicates flashing lights (regardless of colour) are harder for viewer to assess distance, thus at night, two red lights at rear, one flashing, the other steady, can be beneficial.
You might one day see me with daytime lights, as I frequently ride past "your" cricket ground. But bear in mind the only reason I have them is because the switch in the front dyno light is broken and I cannot turn them off! And no flashing lights, thanks.
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gazza_d
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Re: Is a flashing rear light during the day a good idea?

Post by gazza_d »

They don't help in my experience.
I don't normally use them but do have a camera/light combo.on the rear and occasionally I've forgotten to switch the light off. Never noticed a difference whether it's on or not.
I'm of the opinion that you should look as unlike "a cyclist" from a distance as you can, so a single steady light front and rear in poor visibility or at night. Before the pandemic my commute had a direct section of bridleway. It was closed a few winters ago for maintenance and the diversion was down a 40mph toys used as a rat run. When it was dark and dynamo lights on, every driver waited and passed wide. As soon as it became light enough to see I was a cyclist the close passes started.

My view is that any cycle or cyclist mounted visibility said is only useful during day if it improves driver empathy. I don't think that's been invented yet
philvantwo
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Re: Is a flashing rear light during the day a good idea?

Post by philvantwo »

If you want them on your bike put them on, if you don't want any on, then don't put any on!
Seems to be a lot of people on here who can't make a decision for themselves.
Psamathe
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Joined: 10 Jan 2014, 8:56pm

Re: Is a flashing rear light during the day a good idea?

Post by Psamathe »

I keep thinking that on this (and many other controversial safety steps) that there seems no research beyond assuming ultra-cautious or "it's obvious". If Gov. was committed to cycling/cycle safety they'd be commissioning more research to actually get some answers - they do enough for cars.

Ian
drossall
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Re: Is a flashing rear light during the day a good idea?

Post by drossall »

There is research, though sometimes it's inconclusive. Famously, for example, there was research over DRLs for motorbikes. It was a total failure. Drivers on a test track were asked to spot riders with and without lights. They spotted all of them regardless. This gave no information about how useful the lights were, but did show that, with a bit of extra incentive of the driver being aware of being watched, unlit riders could be spotted.

I think I obliquely referred to other research earlier. I believe that other research has shown that DRLs on cars are beneficial. What I'm not clear on is whether that means that cars with DRLs stand out better (seems probable), or that when all cars on the road have DRLs, safety improves, which is not necessarily quite the same thing. If one person in a crowded room is shouting loudly, that person is easy to spot. If everyone does so, life is more confusing than if everyone keeps quieter.

And there's been loads of research on h*****s, but it still needs a whole special board here with no agreement on what that research means.
Last edited by drossall on 2 Oct 2021, 6:44pm, edited 1 time in total.
mattheus
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Re: Is a flashing rear light during the day a good idea?

Post by mattheus »

Psamathe wrote: 2 Oct 2021, 5:51pm I keep thinking that on this (and many other controversial safety steps) that there seems no research beyond assuming ultra-cautious or "it's obvious". If Gov. was committed to cycling/cycle safety they'd be commissioning more research to actually get some answers - they do enough for cars.

Ian
personally, I think it's instructive that no researchers found flashing lights made car drivers safer.
drossall
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Re: Is a flashing rear light during the day a good idea?

Post by drossall »

I think consensus has also been referred to that flashing lights stand out better, but are no good for identifying the distance to the lit object. So, at night, cyclists are seen but then run down anyway because the motorists thought they were further up the road (that's being a bit provocative, but you get the idea!) In daytime, of course, you can use daylight to judge distance. At night, if using a flashing light, use a fixed light for distance indication as well.
Bmblbzzz
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Re: Is a flashing rear light during the day a good idea?

Post by Bmblbzzz »

drossall wrote: 2 Oct 2021, 6:05pm There is research, though sometimes it's inconclusive. Famously, for example, there was research over DRLs for motorbikes. It was a total failure. Drivers on a test track were asked to spot riders with and without lights. They spotted all of them regardless. This gave no information about how useful the lights were, but did show that, with a bit of extra incentive of the driver being aware of being watched, unlit riders could be spotted.

I think I obliquely referred to other research earlier. I believe that other research has shown that DRLs on cars are beneficial. What I'm not clear on is whether that means that cars with DRLs stand out better (seems probable), or that when all cars on the road have DRLs, safety improves, which is not necessarily quite the same thing. If one person in a crowded room is shouting loudly, that person is easy to spot. If everyone does so, life is more confusing than if everyone keeps quieter.

And there's been loads of research on h*****s, but it still needs a whole special board here with no agreement on what that research means.
Before DRLs, daytime headlights were compulsory in some Scandinavian other northern European countries for a few decades. Research was certainly done during those decades which apparently found it improved safety – but I don't know if this was only for car occupants and if it applied in all situations (for instance it might have reduced collisions on gloomy forest roads, which I understand are plenty in Scandinavia, but not in towns).
Jdsk
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Joined: 5 Mar 2019, 5:42pm

Re: Is a flashing rear light during the day a good idea?

Post by Jdsk »

Bmblbzzz wrote: 2 Oct 2021, 7:32pm
drossall wrote: 2 Oct 2021, 6:05pm There is research, though sometimes it's inconclusive. Famously, for example, there was research over DRLs for motorbikes. It was a total failure. Drivers on a test track were asked to spot riders with and without lights. They spotted all of them regardless. This gave no information about how useful the lights were, but did show that, with a bit of extra incentive of the driver being aware of being watched, unlit riders could be spotted.

I think I obliquely referred to other research earlier. I believe that other research has shown that DRLs on cars are beneficial. What I'm not clear on is whether that means that cars with DRLs stand out better (seems probable), or that when all cars on the road have DRLs, safety improves, which is not necessarily quite the same thing. If one person in a crowded room is shouting loudly, that person is easy to spot. If everyone does so, life is more confusing than if everyone keeps quieter.

And there's been loads of research on h*****s, but it still needs a whole special board here with no agreement on what that research means.
Before DRLs, daytime headlights were compulsory in some Scandinavian other northern European countries for a few decades. Research was certainly done during those decades which apparently found it improved safety – but I don't know if this was only for car occupants and if it applied in all situations (for instance it might have reduced collisions on gloomy forest roads, which I understand are plenty in Scandinavia, but not in towns).
Yes, it was. I'd dig it out if it would affect anyone's views...

What seems to have been genuinely missed in the wider implementation of DRLs is the increased risk of drivers not turning on rear lights as it gets dark. But I think that most manufacturers are now dealing with that.

Jonathan
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