Search found 41 matches

by Lesaid
13 Dec 2017, 4:29pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

mjr wrote:
661-Pete wrote:
gaz wrote:Problem two.

I've seen that famous video before - so it wasn't a 'problem' to me any more!

I don't remember seeing that particular one before, but it didn't catch me out. I think that's because my tactic was to watch the balls accelerating/decelerating, not the people (I was expecting they might ask how many passes the group in black made) and the other thing did pass in front of one ball at about 18s, although when looking again, I notice the ball you were told to watch was lobbed high over it.

661-Pete wrote:This video may be of help in refreshing memories of witnesses at the scene of a crime - but I don't see how it helps in persuading motorists to notice cyclists. Motorists should be thinking "there may be a cyclist there" all the time - except when on motorways!

To be fair, that is pretty much the message over the end - the trouble is that they tried too hard to make people not look at the cyclist by misdirecting viewers with a high lob.


If you'd already seen that one - try this. It is a surprising variation on the same theme :)

https://www.youtube.com/watch?v=IGQmdoK_ZfY
by Lesaid
13 Dec 2017, 4:21pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

mjr wrote: a 2005 amendment.


thanks for the link and the clarification.

mjr wrote: Oh, here we go again! Pity the poor motorists, they can't be expected to drive so they can stop within what they can see to be clear if their eyesight is so defective that they can't see far enough at night(!)

I agree with your implication, if not the pointlessly sarcastic phrasing - subject to the caveat in my previous post. Or do you suggest that motorists (and cyclists) all go back to driving at no faster than a walking pace with someone walking in front waving a red flag, just in case of the unexpected? That is the logical extreme to which you are progressing![/quote]

By the way - I observe cyclists to be just as bad, in general, in analogous situations. I often use a shared cycle/pedestrian route - and frequently see cyclists whanging along past pedestrians with dogs and children without slowing down. I have been pressured by an impatient cyclist behind me on more than one occasion when I slowed down from a cruise to maybe 5 mph to go past pedestrians in a non-intimidating way. At night, much of that route is unlit and still has pedestrians on it (and where care with dazzling lights is very relevant!). A similar kind of situation to the things you're talking about, except here, some (not all) cyclists are the 'dangerous drivers'. In fact, part of that route is owned by a local residents association who have in the past, closed it to cyclists because of exactly that problem. It was reopened again a couple of years ago - but it won't stay open if cyclists don't behave themselves.

But leaving aside all the moralistic stuff - and accept that you consider that the motorist is always responsible for any accident regardless of the circumstances - that is your choice. But are you really going to trust your life to the hope that all motorists out there are as good, attentive and 'perfect' as they ideally should be? There are new drivers, experienced drivers, distracted drivers, elderly drivers. Regardless of where you consider blame might lie, don't you want to stay alive? I'm sure you in fact take a lot more care to stay visible and defensive than your comments imply is necessary!


By the way - did you find that data you were talking about that proves the case about better front lights not improving safety when faced with dazzling traffic around an oncoming cyclist? Would be interesting to take a look if you have.
by Lesaid
13 Dec 2017, 3:01pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

gaz wrote:The legal minimum required to be roadworthy under RVLR perhaps? (I feel like a stuck record :wink: ). In setting the standard the governement is telling other road users it's bright enough for a cyclist to be seen by. It is undeniably an evidenced definition and I don't doubt that it was arrived at through research.


I'm sorry, but I don't accept that any such legal minimum standard for lighting or anything else is necessarily sufficient in all circumstances. I think it is foolhardy to trust your life to the principle "because I'm required to have 'that' lamp, that's what I'm going to have and it will be enough no matter what, because the government says it is!". (and based on your next comment, I suspect you might agree with me on that). I'm sure that research contributed towards the setting of the standard - possibly was the main consideration. But I highly doubt if the mandate was to produce a standard that would be fine in ALL circumstances, especially if lighting from other road users has become brighter since the standard was set. I also notice that the standard appears to have been set in 1989, and perhaps, what lights were practicable for cyclists given the technology of the day may have played a role in the decision making. If the standard were reviewed today, would the same levels be set?

gaz wrote:I fully respect the right of any cyclist to choose something better than that minimum, I'd even recommend it subject to the maximum. It is refreshing when another road user accepts it is their responsibility to see a cyclist equipped with just the minimum, recent (short) thread here.


It was an interesting thread. Morally, I agree with you about responsibility to see any road hazard. And I think any of us, if we ran down, say, a pedestrian dressed all in black, on an winding unlit road at night, in the face of oncoming dazzling headlights - we'd all feel guilty and morally responsible. This would be in spite of the fact that there would possibly have been nothing we could have done to avoid that accident, other than drive everywhere at 5 mph, or stay off the roads altogether after dark. So while such a motorist would probably feel responsible, I think it is quite wrong to blame them for such an accident. The pedestrian in that circumstance has to take some responsibility for being visible! Similar with an unlit or poorly lit cyclist wearing dark clothes and no hi vis. Where you draw the line between 'victim fault' and 'driver fault' however seems to me to be an almost impossible moral question!

Lesaid wrote:So - a key question - what real evidence is there that would tell us how bright really does pose a genuine safety hazard on the roads through dazzling other road users (if properly adjusted)? If we had that, then a sensible strategy might be to formulate some rules of thumb aimed at using lighting a somewhat below that level but not too much below since we don't know how dim is sufficiently visible either!

Have a read here, you'll get a few pointers: https://www.cyclinguk.org/blog/chris-ju ... y-dazzlers[/quote]

thanks - I read that closely.

You guys have gotten me interested in this topic now, thanks to all the contributions on this thread (thank you :) ). I'm having a go at analysing the performance of my own front light, to see how it compares with some of the numbers out there - both in lighting pattern, and brightness. Will take a little time though - doing those measurements without purpose-designed and calibrated equipment needs some careful preparation and analysis.

I will also (for my own interest) try to find a lamp of a similar power to the minimum standard, and see how visible it is against car headlights. If it proves clearly visible, I'll eat my words and re-think !! If it isn't, I'll try to find out what it does take to be visible, so far as I can without a specialist lab!
by Lesaid
12 Dec 2017, 11:19am
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

[XAP]Bob wrote:You could see a candle from a few miles away (which I would consider to be at least a reasonable distance) but you couldn't possibly see it amongst the ridiculous shouty 'look at me' powered by hundreds of watts of 'waste' energy from infernal combustion engines.


Perhaps that problem will be of limited lifetime. The Scottish government have announced their intention to ban all-petrol/diesel cars from some city centres by 2032 (I think) - and I'm sure that will only be a stepping stone to requiring all vehicles to be electric (will be fun for the National Grid!). Once that happens, energy spent on lighting will detract from available range. Then there may be an incentive in the motor industry not to provide lights that are brighter than necessary!

But until then, no point in moaning about it - we are where we are and I can't see any amount of lobbying/complaining to anybody causing regulation change that will have any effect in the coming decade, if ever. So - we need to do whatever we need to do to be seen and not rely on car headlights changing for our benefit! Lobbying for strategic cycle routes away from major roads might sometimes get further in specific places - get the bikes and headlights separated from each other?
by Lesaid
12 Dec 2017, 10:27am
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

pwa wrote:The best I've come up with is to do my own tests in the street outside my home with any lights I install. I lean the bike against something, with the lights on, then walk away from it and view it from a distance and from different angles. I'm looking to have it really visible but not dazzling. It's not scientific but it is the best I've got.


similar to me - only difference is I do mine with the bike in front of my car with the headlights on - I want to be able to see the bike clearly against the headlights. I find that my (bright) light is adequate for that, and much less dazzling than the dipped headlights, so long as it isn't pointed up directly at the oncoming drivers' line of sight! Angle it slightly downward (as it has to be for cycling on unlit roads/tracks) and it doesn't dazzle at all (alongside headlights) but is still clearly visible. At 20-30 yards anyway. I've never experimented to see how 'dim' a light will still be clearly visible though.

But as you say, not very scientific!
by Lesaid
12 Dec 2017, 9:47am
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

pwa wrote:For being seen and noticed lights need to be bright enough. Not too bright, just bright enough. And with a wide enough beam to be noticed from angles other than simply straight ahead.


Sure - but, can anyone, even in a specialist forum like this one, give advice on just how bright 'enough' is, based on some kind of evidence rather than guesswork? To be honest - I have no idea how visible I actually am on the road to others - I believe I am as visible as I can reasonably be for the kind of cycling I do, but is that good enough?

I go for a light which can go really bright, and can be run at a reduced brightness when I think that is appropriate. Perhaps even that is too much - but I don't know, and I don't know of anyone that can tell me definitively. Not that I've thought until now of searching for that information (i.e. what range of brightness is thought safe - what is too dim and what is too bright - for different kinds of situations).

So - a key question - what real evidence is there that would tell us how bright really does pose a genuine safety hazard on the roads through dazzling other road users (if properly adjusted)? If we had that, then a sensible strategy might be to formulate some rules of thumb aimed at using lighting a somewhat below that level but not too much below since we don't know how dim is sufficiently visible either!
by Lesaid
12 Dec 2017, 12:21am
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

drossall wrote:Someone more expert will be along in a while. However, "brightness" is a rather imprecise quantity. Some bike lights are heading towards very narrow beams, which can be quite "bright". Car lights by contrast tend to be much larger of course, so would need far more light emission to be equally "bright". This makes it possible for bike lights to have nuisance value.


Think our posts crossed!

For a first pass, I would be inclined simply to check out each of the lights that I have in my bike box - which vary from a claimed 1200 lumen down to an old, 4.5 battery powered filament lamp from 20+ years ago. I also have no idea what the legal minimum requirement equates to in practical terms, so I would want to find that out as well.

If all of these are clearly visible, then there is little point in going further, though I doubt if that will be the case.

I'll also do a bit of hunting in case someone has already done something like this already.

I should thank "mjr" for, maybe unintentionally, pushing me into looking at this more carefully and getting something more solid than speculation to settle the arguments :)
by Lesaid
12 Dec 2017, 12:07am
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

gaz wrote:Unless you have some quite sophisticated measuring equipment you'll gather some anecdote, not evidence.


well - I'm not equipped for lab-style optical measurements, but I can for example, vary the power provided to a light pretty accurately, and I can probably set up to calibrate the output of a light on trial against known references, and to look at the geometry of the beam produced.

On the detection end - what matters is whether a human can perceive it. That bit doesn't need electronics or lab equipment - just two or three people to look and record what they see.

Perhaps could also check how visible the light is to peripheral vision as well.

To do all that will some time to prepare for and set up - but it would be interesting to try. This won't happen tomorrow! Happy to take suggestions and ideas.

Though a very informal first trial with some off-the-shelf lights (I've got a selection) would give a first idea of whether it is worth going deeper into this or whether the results are obvious.

I won't get results sufficient for an academic paper!! But I should be able to get enough to give some idea of what it takes to be visible in the kind of situation we've been discussing. And perhaps settle some of the arguments, one way or the other.
by Lesaid
11 Dec 2017, 11:34pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

drossall wrote: Car and other lights are getting brighter too. The way forward is effective limits on the intensity, design and intrusiveness of lighting allowed to any vehicle.


That makes a lot of sense. I was noticing while looking up the brightness and power consumption of car headlamps for an earlier post, that the brighter offerings were marked 'not for road use'. So I presume that upper limits on brightness are now in place?

But as a motorist as well as a cyclist, I'm fed up with being dazzled by oncoming lights.

However, that isn't going to change tomorrow - or this year, or probably this decade - so in the meantime, surely we have to use lighting that will compete enough to be seen against the dazzle! Bike lights are not going to contribute to the 'arms race' I think, because the upper end of car headlamps will surely always outshine the majority of even the brighter cycle lamps!

I am guessing this problem will not change until the advent of driverless vehicles, whose sensors perhaps won't need viciously bright beams to see where they're going.


On a related topic - I just did a calculation of the width of the foveal field of view at 200 metres. This (according to wikipedea) represents around 1.2 degrees of the visual field (https://en.wikipedia.org/wiki/Visual_field), and by my calculation, corresponds to just over four metres width. So, looking straight down a normal road lane, approaching or beyond 200 metres, the whole lane width should be in the high acuity part of our vision.

So in the particular incident I recounted, 'problem one' in my earlier post is probably irrelevant. Vision should have been sharp across most of the lane from 100 metres distance, and the whole lane before 200m. Assuming I'm understanding the figures correctly.

I was totally focussed on searching for something in that lane, so attention diversion (problem 2) doesn't make sense.

So that leaves the 'expectation' problem that was raised a few posts ago (which I don't believe was the issue as cyclists were in my mind at the time), or simple swamping as above. So for now, I'm going with swamping as the most probable explanation.

So it is back to the level of lighting as the most likely way of decreasing risk. I think I'm going to try an experiment - have someone flash a low power front cycle lamp next to car headlights, and see at what distance the flash is detectable/obvious. Then repeat with higher power ones. That could be a start to establishing how much difference light levels actually make, and quantifying what power of light might be a good compromise for a bike in such circumstances. Collect some real evidence about this!!
by Lesaid
11 Dec 2017, 10:32pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

gaz wrote:
Lesaid wrote:Tell me though - how is that different in principle from the point I was making earlier about lights.

The principle is that speed limits are an absolute maximum and that you should drive a motor vehicle to the conditions within that limit. In the real world when performing a manoeuvre, such as joining free flowing traffic most drivers will allow for other drivers approaching either at or above the limit.

The principle is that a driver should be able to see a cyclist who is legally lit. In the real world when performing a manoeuvre, such as joining free flowing traffic most drivers will blame a cyclist that they didn't see for failing to make themselves visible, even in daylight.

The dangers of driving motor vehicles at excessive speed within the limit are well known and evidenced: http://www.brake.org.uk/facts-resources ... 1255-speed

I've yet to see any evidence that legally lit cycles present a significant source of danger. Feel free to link some stats.


I think you misunderstood my point.

I was saying - or trying to say - that a speed limit is there to limit speed - but you cannot assume because the law says you're allowed to travel at 40mph in a 40mph zone, that it is safe to do so. You have to use your road sense to limit your speed more than the law requires, as prudent.

In exactly the same way, the law sets minimum standards for lighting that cyclists must meet in order to be legal. But you cannot assume because the law says you are allowed to use that level of lighting, that it is safe to do so. You have to use your road sense to use more lighting if the situation needs it.

To me, that comparison is obvious and self-evident, and nothing to do with the kind of criticisms that are for some reason being levelled at my original post on that topic. Sorry if I was not clear enough in the way I phrased it! I think that kind of logic applies to most legal limits of almost anything - not just speed and bicycle lighting.
by Lesaid
11 Dec 2017, 6:08pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

AlaninWales wrote:The evidence of perceptual science informs us that it is the agent looking who accepts or suppresses the information. I.e. it is up to the driver to look properly, aware that his expectations of what might be there will directly affect whether or not (s)he sees everything that is there: Your mind is predicting (in this instance) that there should be no cyclists (because in your opinion the road is too dangerous for cyclists - or as you have posted, because they slow down the (more important) car drivers). In those circumstances, you are likely to suppress evidence of cyclists when your eyes present them to you.


Interesting - I hadn't heard exactly that before, though it intuitively makes total sense. It sounds like a third reason why a cyclist might not be 'seen' in addition to the two mentioned earlier in the thread! Thanks for the link - I'll read it :)

In this specific situation, I don't know if that is the case though it could have played a part. I was looking up an empty inner lane with a bus at a bus stop several hundred yards away. I was trying to find out if the lane was indeed empty, and wondering why folk in the outside lane were not moving back into it after passing the bus, as I would normally expect. Because I was unsure why, and in spite of searching directly along that empty lane, I did not see the cyclist - I chose not to pull out because I was unsure. I was expecting some reason why the lane was empty. This took five or ten seconds. But I must have been staring directly at the cyclist and still did not see him. There was immense dazzle coming from the solid stream of traffic in the outside lane, and the headlights of the bus in the distance.

I 'think' (no proof obviously) that the pinpoint flashing front light of the bicycle was simply swamped by the sea of lights alongside and behind him, and by chance, he didn't happen to cycle directly into line with either of the bus headlights while I was looking. That is why I think a brighter light would have been more visible in that situation. I also think that a steady (not flashing) strong white light on the handlebars would probably have been moving around a bit which might also have made him more obvious.

Later tonight, I'll do a calculation as to how precisely I would have had to have been looking 'at' the bike in order to have seen a faint flashing light, based on the size of the sensitive central portion of the field of view. That might tell me if that issue 'could' have been a factor.

If you or anyone else reading this knows more about this than I do, please jump in :)

AlaninWales wrote:A far more useful response (to noticing that you had come close to killing someone with your car) than blaming the potential victim, would be to consider what you personally can do better so that the situation does not recur. The fact is that the cyclist was there, legally lit and you failed to notice this. The proverbial beam is in your eye, I suggest you investigate how to remove it. Otherwise you are very likely to be in collision with another legally lit cyclist or indeed a legally unlit pedestrian.


Note that I did not move out because I was unsure. It wasn't a case of 'not noticing' - I was searching for something in that lane quite deliberately, and still didn't see him! And I am trying to take action to reduce that risk - one of which is to raise this issue here - though I'm more than a little surprised at the almost universal condemnation of the idea that more than the legal minimum front light brightness might be a good idea in a situation like this !! When I overtook the cyclist a couple of minutes later and glanced back - I could then see a flashing front light, but it was not bright - even when I was just in front of him looking at him in the mirror.

But this thread has given some interesting new perspectives which I'm following up :)
by Lesaid
11 Dec 2017, 5:08pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

mjr wrote: it's rationalisation of "common sense" prejudices and contradicted by other cognitive/perceptual evidence, so let's rely on the cold hard numbers.


I meant to add - where formal research (the perceptual stuff I was referring to) contradicts 'cold hard numbers', you don't throw out either. You work to reconcile the two and find out why there is a contradiction - THEN, you rethink and re-do either of or both of the research and the statistics data gathering/analysis as appropriate, and come to a new conclusion or interpretation.

Cognition, perception and psychology are not my subjects (my interests are in mathematics, physics and cosmology), but it might be interesting to explore this more fully here, if the data really are available and you are up for it?
by Lesaid
11 Dec 2017, 4:37pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

mjr wrote:
Lesaid wrote:You're ignoring all the cognitive/perceptual evidence referred to earlier in this thread. Whatever!!

No, I've replied to it in the earlier thread. I didn't want to rehash old points, but as you insist: in short, it's rationalisation of "common sense" prejudices and contradicted by other cognitive/perceptual evidence, so let's rely on the cold hard numbers.

Lesaid wrote:Have a good Christmas!

Please stop that. I'm what people like you probably call a heretic (if you're being polite).


ok then - I'll bite. Can you show me the statistics that relate to the kind of accident which involve a motorist or pedestrian seeing (or missing) a bicycle coming towards them in the dark on a busy road? That is the specific kind of circumstance for which statistics would be relevant here.

More general statistics that include incidents in daylight, or involve seeing the bicycle from behind or the side are irrelevant to this issue and would just obscure the evidence that we're looking for.

If you have such statistics from a credible source that show that my views are wrong, then I'll apologise and rethink my views.

By the way - you can't write off that perceptual evidence with a handwave - they are the results of serious research - and it seems highly reasonable to assume that the findings would apply to motorists and cyclists just as much as to people in other kinds of situations.

I have to admit - I didn't rise to your comments about formal statistics before because I assumed that such statistics would be unlikely to be broken down in a useful way for this circumstance. My apologies if I was too hasty in that. I am not a religious person and I do seek evidence where available to find and support conclusions.
by Lesaid
11 Dec 2017, 4:08pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

mjr wrote:The worry is that it leads to the deaths of others


Exactly !!!

You're ignoring all the cognitive/perceptual evidence referred to earlier in this thread. Whatever!!

Have a good Christmas!

:)
by Lesaid
11 Dec 2017, 2:09pm
Forum: On the road
Topic: Near miss on busy road - plea for good lights!!
Replies: 112
Views: 6499

Re: Near miss on busy road - plea for good lights!!

"mjr" made all sorts of points.

Just to note - I never said this specific type of accident was the most common kind, or even was common at all. But it is a kind of accident with potentially fatal consequences for both the cyclist and other road users caught up in a possible pile-up. I can well believe this is totally consistent with a statistic that said bike lights were a factor in less than 2% of accidents. Doesn't help you if you are in that 2%.

But not going round the same points again. Folk can scan back in this thread to find the arguments. You hold your beliefs and that is your right. I will stick to mine - and I personally think I will have a better chance of living longer. I might be wrong - in which case I will have to take the consequences!

Thankfully on the particular road in question, which I have to use daily as it is en-route to and from where I live, it isn't a common problem as very few cyclists use that road at peak times. This could well be because of the intimidating high-speed two-lane continuous traffic and the presence of alternative cycle-only routes for most of that road's length which many cyclists (for some reason, not all cyclists!) choose to use. And this, in my view, makes more sense than using that road even with bright lights!

Have a good Christmas and stay alive!