Another "solution" to the fireworks show is to close your eyes until the fireball passes with his brilliant self.

You do understand what lux is a measurement of, don't you? If a source of light spreads the available lumens over a greater area, the lux is lower and the ability to 'blind' someone is greatly reduced. The light may have a lot of glare but hardly 'blinding'. If the beam is tight and the lux is high, the ability is 'blind' a driver is also reduced because it's tightly constrained and has much less glare, although it would be brighter if seen from directly ahead. Since we don't tend to ride over where the drivers are, a tight beam isn't going to be a problem either.

The fears about blinding drives are overblown. I'm using 1440 lumens right now and haven't blinded anyone yet. Compliments or complaints about how bright my lights are are just confidence boosters to me and really just encourage me to buy more powerful lights to be seen better than ever before. You saw me!

+1

Bingo!! You get the prize!!

That's easy, To cut down the glare.

I am sure you don't think that you are dimming your lights because others are looking directly at your lights? Please tell me you are not thinking that!

Next question..

That's exactly what I was going to ask you guys, but with respect to blinding bicycle lights.

No one is saying the problem is because they're looking at the lights. You don't need to look at it to be blinded - a bright enough light, close enough (a few feet, from a passing cyclist) and aimed at your face will blind you.

We dim our lights while driving because "looking away" is not a workable solution.

The bicycle, riding in the lane or even moreso as far right as practicable, isn't going to be much problem to drivers unless the light is aimed at them. Or helmet mounted and pointed at drivers. If someone is set up reasonably, nothing needs to change there. But put those lights four feet laterally from a passing cyclist, aiming one or both lights down the road, and you'll eventually cause an accident.

On the MUP, yes, headlight glare can be an issue when oncoming lights are aimed too high. The path is too narrow to move laterally.
Riding behind somebody with a strong taillight (eg: group ride) gets rough too.

But most of my routes 200 lumens is woefully inadequate.
I run a magicshine ("800 lumens") on the handlebar and a cygolite (I think 350 lumens) on my helmet.
Even with all that, I frequently outrun my lighting on some steep descents going ~35mph on cracked pavement with some sand/gravel. Many of the roads have no streetlights and have little ambient light.
And there are still drivers that don't seem to see me at intersections while I'm panning my helmet light across their car mirrors/driver's face.

If I see that the magicshine is aimed too high, it's easily re-pointed on the roll. I also will use a hand to shield it if it's pointed into another cyclist's face.

In all due respect sir, you are 1000% wrong on what I have in bold. Almost to a man, everybody that runs bright lights, say they aimed their lights downward, each and every one. I don't think you can find a post anywhere where the poster says they aim their lights at people's faces. The start of your reply is a 1000% wrong, so that taints the rest of it.. Just telling you like it is...


Says Who????What about the 1000+ car drivers that DON'T dim their lights, and if they do, they daggone sure don't dim their lights for bicylists!!

+1 - This is probably my favorite post in this thread so far. Well, except for mine - - Your experience with your lighting is the same as mine.

How can I be wrong? I'm giving you personal experience from the receiving end - what the guy who's aiming the light says is irrelevant.

I am 100% certain.

They dim them for other drivers as required by traffic laws. It is required because asking the other driver to simply look away would be ineffective and unreasonable.

CE, not every bright bicycle light is a problem. Some of them are serious problems. I think the only way to really be sure is to prop the bike up one night and walk or ride by.

Yours was the one I was hoping to top!
When people first asked me where I got my my light it was easier to answer as I only had 1. Now I wonder which one they're referring to.

One thing posters haven't mentioned is that most cars now have tinted windshields & the tint (even stock) is often darker than that of a generation ago. So motorists being blinded by bike lights is even less of a problem. Actually I've driven some friends cars with dark stock tint & don't like it at all, it makes it harder to see non-lighted stuff at night. It's a good trick to get car buyers to pony up for HID headlights? So anyway maybe we need brighter bike lights just to compensate for tinted windshields & distracted drivers. Durn y'all, now you've got me thinking about replacing my 300 lumen CygoLite! But first on shopping list is a nice tail-light like the Dinotte.

I am thinking over my driving experiences, and I can't think of why or when I've had a cyclist be a few feet away from me and oriented in a way that put his light in my face. That would put him pretty much climbing my hood, about to be annihilated in a head-on. Look, the only time cycles and cars are a few feet apart, the car is passing the cyclist, or the car is stopped and the cyclist is crossing at the pedestrian cross walk. The driver isn't getting any face-on from the cycle's headlight. Turn it around, I am thinking about my riding experience, and similarly I can't think of when I have been a few feet from a car with my bike headlight pointed at his face. Even with the helmet light, when I have deliberately put the spot on a driver, I've been 40, 50, 60 feet away - approaching an intersection where the car is creeping out on the cross street, or approaching an intersection where the car is approaching from the on-coming direction.

There is only one time I've put my helmet spot right in a driver's face from just a few feet away. He had just swerved toward me from behind on a bridge, honking and accelerating away. Stupid prick. He didn't think about the traffic lights on the road after the bridge. I caught up with him as he sat at a red light, from a yard away, put my rated-1000-but-really-600-lumen helmet spot right in his night-adapted eyes as he ranted about me not having license plates, with his eyes closed, hands over his face. I imagine he was seeing spots after that. Gee, I feel so bad, I "blinded a driver".

I was driving around tonight doing Xmas shopping, and I saw a lot of cyclists. It was dark and raining, water streaming on my windshield, reflections on the slick black streets, stores lit up for shoppers, cars and bikes criss-crossing in the tail end of rush hour. The cyclists with a single weak light - like an AA-powered Planet Bike light - were hard to see, especially if they were wearing dark clothing. They were just dim little lights bobbing along amidst the glare from car headlights. The cyclists with bright lights on their bars - I'm guessing 300-500 lumen rechargeables - were more noticeable, but if their clothes weren't reflective, it was still easy to overlook them, as I was peering through my dripping windshield for cars and pedestrians. The riders with bright and blinking lights, or with bright lights on both bars and helmet, were pretty conspicuous. The blinking immediately communicated "bicycle". The dual bar and helmet lights somehow gave the rider a size, a stature, that communicated "person", and the helmet light also attracted attention by its waggling movement. In all cases, reflective clothing helped a lot, by outlining the rider's form and by moving as he pedaled. I was also reminded of how easy it is to be right hooked. Even if you do look over your right shoulder as you prepare to turn right, it is very easy to miss a cyclist approaching in the dark. His bar-mounted headlight is actually below the belt line of your car. I will be even more careful to play my helmet spot over the cars' right side mirrors or even their rear view mirrors.

Good points there!! That 300 lumen Cygolite would be just the ticket for a rear light!!

But, in all honesty, get some more lums. IMO, the more lums, the safer you are out there.. I tell everybody, that when we ride our bikes, our whole family is riding with us. Anything happens to us on the bikes, flows right back to our family. Brighter lights = more safety, I don't care how the "light police" scream and holler, tis the truth!!

Good post, good points. I would rank this as my third favorite post of this thread.

The "thing" is, those of us that have a lot of power on our handlebars are not running around defaming bicyclists or blinding drivers. In the real world, with lit signs and streetlights and automobile lights and warning lights and glare off of wet pavement it feels good to stand out. If someone aims a high-powered light so it shines directly into oncoming traffic, I agree that is an issue - but I don't think anyone with a brain would actually do that. No one that has posted in this thread is doing that. There may be studies and experts that "prove" we are causing accidents and blinding people, but in our real world experience (I'm almost 60 and have been riding with bright lights for 40+ years) it just ain't happening.

And I am sure you are 100% sincere too. However, I beg to differ. Trading words across the internet won't convince either one of us to go to the other side of the debate. What would makes up come together is that we could both ride together in each of our environments That way, you could see first hand what I am talking about, and visa versa, I could see first hand what you are talking about.

You jest, but a 300 lumen Cygolite pointed rearward wouldn't be a bad idea in some circumstances. If I am riding directly into the setting sun and cars coming up behind me are going to be blinded by the sun, I take one of my 650 lumen NRs and snap it onto the seatpost in flash mode. I would of course prefer to not ride in that circumstance, but occasionally I have to and with the NR on flash the approaching cars steer clear, even with the sun in their eyes. As soon as the sun is no longer an issue, I put it back on the handlebar with its partners.

Don't misunderstand, I'd set up like your's if most of my riding warranted it. Brighter is better but I don't even use a light for eight or nine months of the commute. If I needed more I'd want your setup no question. I'd have to just tone it down on two-way bike paths.

No need for big light on MUP trails. My helmet light gets switched off then.

In theory that all sounds good - in practice the details and specifics mean it doesn't work. What happened to your trig?

A 10 degree beam at 100 feet is about 17 feet wide and only 3.4 feet wide at 20 feet. At a distance of about 40 feet it would encroach on oncoming traffic, and after that it would become increasingly LESS of a problem.

A 35 degree spot is 60 feet wide at 100 feet. That's going to encroach on oncoming traffic regardless of the distance because its still 12 feet high/wide at 20 feet and 6 feet high/wide at 10 feet. And yeah - there's less lux in a flood at any given distance because the beam is spread over a wider area, but light intensity is still proportional to the square of the distance. So the closer you get to a flood the more of a problem it is. And in this case - fr 40 feet on - the problem is AMPLiFIED as you get closer.

The problem is under-rated. You evaluate the brightness of your light by how much light is reflected BACK to you - in whats pretty much the opposite direction the light is pointed. Probably only a small fraction of the output. Anyone on the recieving end, on the other hand, has to deal with a much larger percentage of the output.

I have 35 and 15 and 10 degree spots and did some pretty thourough real world testing complete with photographs to confirm that. LOL Glare? From a distance of 30 ft onwards on a bicycle path, while walking towards my bicycle (that had my helmet resting on the bars with a SSC P7 Bin D emitter and a 35 degree collumnator, aimed downwards to light up the path) - not only could I not see the bike - I couldn't see the bike path or the grass on either side of the bike. And the closer I got - the less I could see around me - even averting my eyes. At a distance of 10 feet I didn't have a clue what was in front of me.

That basicly forces oncoming cyclists to blindly aim for your left side and pray. Motorists may have a larger lane to deal with but that only reduces the issue - it doesn't eliminate it. The beam coverage on a 35 degree flood is still high enough and wide enough that, unlike automotive headlights that are mounted lower and have a cut-off - it'll hit their windshield.

Which is another reason I drive with shaped beams - they not only put more light where its useful - they're less of a problem for other people on the road. But those have limits too. Put out 10,000 lumens from a shaped beam and you'll still have so much light being reflected forward OFF THE ROAD, that you'll completely dazzle oncoming traffic.

Because a low beam is a lower powered SHIELDED element that uses only the reflector and has mo direct forward output. That effectively reduces both the reach and brightness of the light.

It should be worth mentioning that its illegal to use high beams within city limits, or on highways with overhead lighting, or within specific distances of oncoming traffic - which doesn't mean its OK to stare at low beams.

It is the unexpected that sometimes creates the need. For example, I was riding home on a MUP during daylight hours with helmet & handlebar headlights turned on. Bright lights, not a weak AA. A young woman riding the opposite direction came around a corner into my side of the MUP. I was on the far right side (my right). She saw the helmet light, veered to her right & ran head on into a young man riding to my left. That helmet light saved me from a collision with another cyclist during daylight hours. Both cyclist were injured, not severely. But, the young woman probably had a concussion & the young man had a dislocated finger, a destroyed $500 front wheel, & road rash.

I keep the lights on (helmet & bike mounted) all the time riding no matter the location or light conditions. I have had motorists pull up to me while on a group ride & comment on how well they can see me.

Don't discount the value of lights no matter the location or conditions.

And no one admits to passing gas in an elevator or on the subway but "someone" does it. Some cyclists are riding up and down streets and paths with excessively bright lights getting complaints and yet their response at best is "mission accomplished," as posted recently on BF by some cyclists of Light Power Ranger Brigade

I see your trig and raise you an area. A 10 degree light at 100 ft would cover 227 sq ft of area (assuming a perfectly round beam). At 20 ft, it will cover a 9 sq ft of area. A 35 degree beam would cover an area of 2827 sq ft at 100 feet and would cover an area of 113 sq ft at 20 feet distance. Let's assume that the lumen output of both lights is the same and, for convenience, it's 1000 lumens. Now assuming a completely even light coverage over the entire beam, i.e. a beam without hot spots (not realistic but easier to calculate) we get the following: For the 10 degree beam, the lux (lumens/sq m) is 47 lux at 100 feet and 1200 lux at 20 feet. For the 35 degree beam, the lux would be 3.81 lux at 100 feet and 90 lux at 20 feet. For comparison (and from Wikipedia), the a full moon has a lux of .2 to 1 lux on a clear night. A light in a living room has a lux of about 50. An overcast day has about 1000 lux.

So at 100 feet, a 35 degree beam is about as bright as the full moon...hardly blinding. At 20 feet it's a bit brighter than a living room. The 10 degree beam isn't as bright as a living room...let's say a romantically lit bedroom...at 100 feet. It is damnably bright at 20 feet...if you consider an overcast day to be blindingly bright.

Don't forget that the measurement for the beam width has to be split down the middle so the wide of the 35 degree beam is only 6 feet into an 11 foot wide lane (standard lane width is around 11 feet without a shoulder). Assuming that most cyclists ride near the edge of the road, that puts the beam at around 5 feet from the center line and cars don't crowd the center line all that much...usually. For the 10 degree beam with 1200 lux at 20 feet, the on-coming cars are going to be about 10 feet away from the edge of the beam.


Nope. We aren't talking about a surface that is even remotely reflective. The light coming off of the bike and striking the ground is being absorbed or scattered by the black pavement. Very, very little of the light is reflecting of the pavement in a forward direction most of the light is scattered backwards toward the rider (or driver). If you ride in the rain, there is more light being reflected...it's why we can't really see our light on the road during rain...but the angle of incidence is all wrong to get light into a driver's eyes...especially if the driver is too far outside the beam for it to matter.

There is a way to avoid the bike path problem...avoid the bike paths! I don't ride bike paths at night, full stop. I don't do it for 2 reasons. First, all of the bike paths in my area close at dusk. I'd rather not explain to the park police why I'm violating the law and, more importantly, spend my time in court. I particularly don't want to spend my money in court. The second reason is that I don't want to be shining my light in the eyes of other trail users...who shouldn't be using the trails either.

Problem solved.

I sold my dinotte for 50 bucks and bought two cygolite hotshots. $25 for 70-80 lumen (vs ~115 lumen) is pretty good QPR.

and all of this talk of outrunning your light at 35 mph is so 2012. in 2002 a properly focused 200 lumen light would have been wicked bright and sufficient for said descent.

its also important to note that many lights have far fewer lumens than advertised. the magicshine 1000 is really a ~600 lumen light and the cygolight 600 is a ~470 lumen light.