I think you can apply the same principles to bike lights when you start talking about the high output units. There are very good reasons that car headlights have regulated height requirements (max of 44 inches in Oregon). It doesn't matter how visible you are, if you blind someone (even temporarily) they aren't going to see anything.

Cyccommute: I consider temp blinding to be similar to undialatting(sp?) someones eyes and the recovery time until they can see properly in the darkness again. This time varies from person to person and their reaction to the light also varies. You can see the effect yourself. Go outside at night and let your eyes get used to the ambient light. Now look right into your bike light and then look around. It might not create full blindness but it can create impaired vision, certainly tunnel vision is many.

That has not been my experience with either my lights or with other bicycle lights I encounter. Generally speaking, if a cyclist invests in expensive bright lights, they point them so that the lights illuminate the bicycle's path (yes there are exceptions). That generally means the light is aimed at the ground a few feet in front of the bicycle because that's where they are most effective. My lights are aimed about 3 car lengths in front of my bike. That's aimed far lower car lights are aimed.

By the way, I don't strobe my front lights...ever! I spent money to get light so that I can see the road. I use the lights to see where I'm going. If you can see where you are going, cars can see you.

Same here. I read more than a few comments here about people aiming them at driver's eyes and "wanting to be seen" and that's what I was talking about. My high output lamp is aimed so that I can see. I have a small USB rechargeable flasher on the front for visibility.

You got that right!!

First off, I am used to cars and trucks coming down the highway with superbrights on. If they blind me, you are correrct again, I shouldn't be on the road. Simple as that.. There is no HEADLIGHT POLICE out there, furtherless for bicycles. But, there is the real danger of not being seen on two wheels. That danger must be dealt with, way before we even look at bicycle lights irritating drivers. If bicycles are not seen, we in a world of trouble. If they gave me a dollar for every motorist that has been blinded by bicycle lights, I be in the poor house. If they gave me a dollar for every accident that bicycle lights have caused, I would be 20 levels below the poorhouse!!

Actually there is. I was talking with a LEO last night on my regular ride who was sitting at the entrance to a cul-de-sac. And he told me that he does in fact pull over and ticket motorists for driving with their high beams on while driving in traffic.

blind, verb (used with object) to make sightless permanently, temporarily, or momentarily, as by injuring, dazzling, bandaging the eyes, etc.: The explosion blinded him. We were blinded by the bright lights.



Defining "blinding" as only complete loss of vision has no legal or linguistic basis.

"Blind" for driving purposes is not complete loss of vision, there are plenty of people who can read a book and walk without a cane but are legally blind.

As a practical matter, I can guide a car down the road without my glasses on, even though I can't read the speedometer. But legally, if I couldn't correct my vision, I'd be too blind to drive.

When you say you've never been "blinded" by oncoming traffic, do you really think you could pass your driver's license eye exam while those lights were still shining in your eyes? That's what "blind" means for driving.

That's also a favorite primary offense for pulling over drivers who might be impaired -- if you're too distracted, inconsiderate, or impaired to turn off your high beams in traffic, that's probably not the only threat you pose to others.

The requirements for motor vehicle headlights also restrict where they're aimed and how the light is distributed within that pattern.

For single-beam headlights, Washington's rules specify

(1) The head lamps shall be so aimed that when the vehicle is not loaded none of the high intensity portion of the light shall at a distance of twenty-five feet ahead project higher than a level of five inches below the level of the center of the lamp from which it comes, and in no case higher than forty-two inches above the level on which the vehicle stands at a distance of seventy-five feet ahead;


Stop your bike 75 feet away from a reflective road sign. Does any of the high-intensity light hit more than 42" above the road? If so, your light wouldn't be legal on a motor vehicle.

Let's look at it from the other way: Have you ever been 'blinded' by on-coming traffic to the point where you couldn't see the road and/or couldn't continue driving?

Looking at it still another way: If you have been irritated by an on-coming car's lights, which one has irritated you? Driver's side or passengers? Now consider that we cyclists exist on a part of the road that is to the right (US) of the passenger's side light. That's way out of the sight line of an on-coming motorist. They may see a little of the side spray from our lights...which is good...but the brightest part of the beam is going to be directed away from their sight line.

Yes, absolutely. It happens at least once a winter, usually someone with their high-beams on, or with poorly-aligned low-beams. Sometimes a "lifted" truck with illegally-high headlights, or an idiot using off-road driving lights on the road.

It happens more often to my wife, whose post-cataract night vision is still legally adequate, but more subject to night-time glare.



It varies -- if it's a high-beam headlight, even the passenger-side high beam throws part of its high-intensity beam into the oncoming lane.

If it's an alignment issue, either low or high beam from either side could be shining into oncoming traffic.

A bicycle headlight will typically be somewhere between the two headlights of a car, a bit to the left of the right wheel track of a car, so it doesn't take that much misalignment for a bicycle to be shining part of its high-intensity beam into the oncoming lane. (Gutter bunnies are further away than competent cyclists, and less likely to have adequate lighting, so their headlights are less of a concern for oncoming traffic.)

Brilliant - I suppose "Dazzling" is more what I meant by blinding, but you hit the nail square on the head there.

BTW, just because cyclists should be off to the passenger side of the vehicle, doesn't mean they are. It like saying all motorists obey the speed limit.

And going back to the F=MA equation posted a while back - that is the formula (in its most basic form, and therefore not entirely accurate (but good enough)) for linear momentum. and it is one I explain to people regularly.

Being a "professional driver" you are more likely to have people step out in front of you (FACT) because they perceive you are more likely to see them because you are trained to a higher standard.

Now in this country (UK) there is a speed campaign that go along the lines of "Hit me at 40MPH and there is an 80% chance I'll die, hit me at 30MPH there is an 80% chance I'll live" - This is aimed at car drivers.

MGW of the average car is 3 tonne. Remember F=MxA - 3x40=120, 3x30=90. Now lets drop the speed again, lets say 5MPH - 3x5=15

Now factor a bus into the equation. An unladen single deck bus has an average weight of 13 tonnes and an average capacity of 60 people. For loading regulations, I belive it is calculated that 15 people average 1 tonne - so a fully loaded average single deck bus is ~17 tonnes. F=MxA - 17x5=85 not a lot different from 3x30=90. I always tell people that a bus traveling at 5MPH CAN kill, and does about the same amount of damage as a car travelling at 30MPH - they never believe me untill I tell them F=MA.

Dam Dig, I thought I had a long sig!!!

On the LEO giving out tickets for driving with the high beams on, well, I could compare that to a LEO giving out tickets for JAYWALKING!! What I am saying is, giving tickets for High Beams is as rare as giving tickets for Jaywalking!!

On that answer, I have to take this to another level!!


I agree 100% in what cyccommute stated. If you get blinded on the highway from high beams, you shouldn't be driving!! Period!!

From my experience in driving on the road for many, many years, I can see high beams coming at me out my peripheral vision. From my experience, I know not to LOOK directly at them, instead look where I am going. That's nothing but pure common sense!

For some reason this isn't widely known, but you can make eye drops out of the histidine-rich dipeptide l-carnosine that to some extent will improve the clarity of the lens in your eye by reducing the rate of glycation, (the formation of advanced glycation end products) The outer part of the eye is made of proteins called proteoglycans which are particularly subject to this process - its one of the most destructive of many processes of aging because it stiffens your blood vessels and causes decreases in circulation and hypertension. Its (probably) not currently reversible (at least a therapy that was supposed to be available to reverse it for some reason has never made it to market) However, topical l-carnosine diluted in saline helps keep it in check and over time it can do really miraculously positive things for some people's vision.

A very similar (patented) therapy has been proven (in a commercial product that costs an arm and a leg) to reduce glare. The big secret is that the unpatentable l-carnosine therapy does the same thing. But, you have to mix up the eye drops yourself, every other day, and do it for a while. DO NOT KEEP THE UNUSED DROPS LONGER THAN 48 HOURS and refrigerate it. Keep it ultra clean. Wash your hands before you mix it.

It really works well. I did this myself, and it made a HUGE difference. I used commercial small dose saline droppers and mized a very tiny, premeasured amount of l-carnosine.

I'm not kidding, it was like a miracle. This therapy is also REALLY good for old dogs who are going blind, it visibly clears up their cloudy eyes.

Also, take lots of berry supps. And other antioxidants. A number of berries offer really substantial protection of the cells in the eye from insult.

There are lots of obscure cheap and effective therapies for common illnesses that are just ignored because nobody thinks they can make money off of them. This is a good example. They would rather give a few people surgery and write all the rest off.

LOTS.

So do you pull off the road and let your eyes readjust? If you are 'blinded' and can't drive safely, I certainly hope so. If you do pull off and let your eyes readjust, how often do you have to do it? If you, or anyone, have that much trouble with bright lights I would hope you would take yourself off the road so as to not endanger all the other road users.

Where the a bicycle light is in relation to other traffic is dependent on the road. Riding to the left of the right wheel track probably isn't the most usual spot for a bicyclist to ride at night. It's still a long way from a on-coming motorist and further away then the driver's side light of another car.

"Dazzling" isn't the same as blinding. You, and others here, are talking about a level of glare that can be uncomfortable to be sure but it doesn't rise to the level of impairment that would cause a driver to be unable to continue driving down the road. The use of 'blinding' used here is more along the lines of a conversational 'blinding' for which dazzling is a very good synonym. I too have been 'blinded' by the glare of other car lights or the sun or light reflecting off snow etc. But that is a comfort issue and isn't likely to cause an accident or even more than a momentary discomfort.

Then there is the clinical definition of blinding which could cause more than momentary discomfort and could lead to an accident. But another car light or a bicycle light or even sunlight isn't likely to cause that kind of permanent blindness.

On the other side of the coin is the motorist. Motorists don't think for a single instant about whether or not their lights are blindingthe cyclist ...not simply dazzling but truly depriving them of sight...on the side of the road. They hardly thing an instant what effect their lights have on other motorists.

After talking with him. I got the impression that he does ticket drivers with their high beams on in "regular traffic" on a regular basis. But, yes, in general I agree that it is probably as ticketed as often as jaywalkers are.

I'm struggling to find momentum in F=MA
https://lmgtfy.com/?q=momentum

Regarding dazzling/blinding.... only time I've had to pull over and stop was on a small rural road. Turned out it was a tractor, well off the road in a paddock with a giggawatt spotlight pointed down the road.

CC,

I have to agree with you on that. I've lost track of the number of times (in a day/night) that I've been "blinded" i.e. dazzled by a motorists headlights.

More than once I've had to put my hand up in front of my face to shade my eyes and they still don't seem to get or care that they're "blinding" me. And as I've said somewhere in another thread. At times the so called "professional" driver seems to be the worst of the bunch. As I've said I've been buzzed by cab drivers i.e. a professional driver and when I've called the company to report it. The dispatcher takes the attitude/position of "he didn't hit you so what's your beef?"

Also for the person who commented that it's only a matter of time before the law "catches" up with the bicycle lighting industry. And laws are passed either limiting the power of or angle of bicycle lights or presumably the number of bicycle lights. Don't forget that unlike a car/truck where once the angle of the headlights are set. It takes a substantial amount of force to knock them out of alignment. That with a bicycle (even I would imagine a full suspension bike) that a bumpy road can knock them out of alignment. Also don't forget that there are some jurisdictions that limit the number of lights that one can have on their bikes. Fortunately for me Florida is NOT one of them. But we've had at least one member posting that where they lived there were laws in place limiting the number of lights that they can have on their bikes.

Here in Florida even though the law requires one headlight and one taillight that is visible at x distance. It does encourage the use of multiple lights.

I fully agree that we should do our best not to have our lights setup so that they shine right in the eyes of other road users. But the reality is that unless one mounts their lights somewhere on the fork of their bike(s). That at some point they are going to shine in someone's eyes. It doesn't mean that the cyclist has done it on purpose. It's just that with most headlights being mounted on the handlebars that's where they're sometimes going to shine.

And maybe, just maybe if motorists weren't in such a hurry to get where they were going and slowed down. They wouldn't have to worry so much about being "blinded" i.e. dazzled by another vehicles lights.

I have been reading and commenting a lot in this thread, however, I have YET to see any comment of some one purposely saying they are "aiming that at driver's eye"... The phrase "wanting to be seen" has been used a lot, and I for one, make that priority one. But, they are vastly different statements.

Could you kindly show US the poster and statement where they say they are "aiming at the driver's eyes"?

Thank you kindly,

I await your reply..

That is the whole clux of the debate. Sheesh, if cars acted sanely, I think I would feel safe with only a pen light!! However, we all know the danger out there and the recklessness of the cages, and we must make being seen a priority. If we don't, the odds are against us when we ride on the road.. On the bike trails, not a problem, but riding in traffic as in a commute, that is big time dangerous!

Well the choice of the algebraic notation was not mine, but the equation still stands. The first link from LMGTFY is this - https://en.wikipedia.org/wiki/Momentum

Force = Mass x Acceleration was probably the wrong units, but the equation still stands to give a basic understanding of how much damage something is likely to do - the bigger the product the greater the damage.

And whilst we are back on this subject, I just did some of my Driver CPC training today.

Quite interesting - did you know that a fully sober, fully alert person takes on average 0.7 seconds to move their foot from the accelerator to the brake pedal this is before braking has started. A bus travelling at 30MPH will have traveled around 43 feet in that 0.7 seconds !!!

It wasn't harsh at all, I was simply presenting the facts. Of course you could vary the brightness, to a point, by varying the voltage, but it wasn't caused by the voltage change - it's because you were pushing more current through the device. LEDs emit photons when charge carriers (electrons and holes) recombine in the vicinity of the junction. More charge carriers means more light. The number of charge carriers flowing in the circuit is the very definition of current. If you are arguing that LED brightness is a function of voltage, then you are quite simply wrong, whether you are willing to admit it or not - you are arguing against well-established facts.

Sorry if if this sounds thick - but if you can vary the brightness of a LED by changing the voltage, how can you say that the voltage change is not what causes the LED to dim or glow brighter.