I recently started using a Cygolite Rover II. It's great so far - even on low it makes a great headlight for darker areas (mostly MUPs after dark - all roads are brightly lit) - far brighter than my Cateye EL320. The problem is when the light is on flash mode every sign with a reflective surface within a few hundred yards flashes brightly - literally signs WAY down the road are clearly picking up the light brightly. I've checked and it only seems to flash in its brightest mode. I'm usually biking around Boston so there are tons of signs. I came up to one intersection and it looked like a dance club .

As much as I think it's cool I'm sure it's distracting to motorists and some may be wondering where the &#&#*@! is that light coming from when I am a few hundred yards away . I'm willing to bet that people can see me coming from a mile a way though which is probably the point.

Do you have the light aimed down a little to illuminate the road surface? Your lights are supposed to let you see and be seen.

If it can shine through the clothing of pretty women, it may be too bright. Or not.

dude... i cross paths with all sorts of jerks blinding people with their bike lights. a poorly positioned quality light can be too bright.

I use the same light. If it's lighting up too much, aim it down. Also, I only use the flashing mode in daylight riding. If I can see the light beam on the road I leave it in a constant on mode. I think it attracts more attention as a "be seen" light during daylight hours in flash mode. At night if I'm using it as a "see" light, I want it on all the time.

Haha seriously! As soon as I hit the MUP the light goes into low steady mode to work more like a headlight. Believe it or not the light is tilted down a bit when flashing - enough to light the road a bit. Perhaps it could be tilted a bit more.

One night some guy came at me with a Magicshine on high positioned on his helmet. I had to stop the bike and wait for him to pass because I couldn't see a thing beyond the light. Hopefully I didn't blind anyone like that!

If you need a more attention-getting be-seen light for nighttime, you can get one of those little button-cell squeezy flashlights and set that on blink, then use both lights together. It's easier to identify a white light as a cyclist if the light is flashing. Otherwise it can look like a porch light or whatever. But steady light is supposed to be easier to judge distance on, so it seems like a good idea to have both.

A poorly positioned low quality light can even be blinding. Now it's even worse with 400 - 600 lumen systems in a more affordable price range. I make sure to steer clear of the MUP for at least 2 weeks after Christmas because that's the highest probability of running into someone trying out their brand new twin-head helmet mounted 800 lumen photon torpedos, and not understanding that you don't look at the oncoming traffic when you have one of those.
I use an Edelux on one bike and an IQ Cyo on another, and both are extremely bright but have cutoff optics to keep from blinding oncoming traffic. My Supernova E3 is a symmetrical lamp and does not afford that luxury, but I've stopped using it since getting the Edelux. Although, when I used it I kept it drive side mounted, below my handlebar bag to reduce any blinding effect by keeping it low and away from traffic.

I wear a 600 lumen light on my helmet in the winter. If I had a brighter one, I would wear it.

But with a bright light comes responsibility and the need for courtesy. Don't shine it at oncoming cars (unless they are oncoming directly at you, or course!), and aim it off to the right (or cover it with your hand if it's handlebar mounted) on the MUP when passing oncoming cyclists.

Yes, lights can be too bright. That's why car high beams aren't on all the time.

As Clifton says, even dimmer lights shining right in your eyes can be blinding. Anyone who has been camping with a bunch of rookie cub scouts knows this first hand.

Last winter I did a homebrew light setup. Powering two 20watt 12V MR16 bulbs in automotive housings off a 7AH 12V SLA battery. I received several complaints and saw people covering their eyes on the local MUP with one being aimed upwards and the other more downward.

I changed to a smaller battery and am using one 35watt bulb now, much less complaints when its aimed properly.

ARGH definitely they can be too bright. There's a long cycle path through the middle of Hyde park in London which can be pretty dark on a wet winters night. Ordinary LED lights are perfectly visible in those conditions, but someone would always come along with some kind of nuclear fusion powered gigawatt arc-light strobing away on the front of their bike. When the light is on it hurts your eyes and when it's off you're still blinded and can't see where it came from, making it very difficult to know where they are, like some kind of nightmarish quantum physics conundrum. An electron in a cloud chamber. You just have to stop and close your eyes and wait for them to pass.

Please. Dont. Do. That.

The fact is, we are sharing the roads with distracted drivers, given that, I want to be the distraction. Very bright lights help.

I don't normally need lights to see by, only to be seen, so I use a 1W PB Blaze in flashing mode. One bright, sunny day an oncoming cyclist asked me to stop. Upon stopping he informed me that he was an epileptic and that my flashing light could cause him to have a seizure. After a long deliberation (and posting a new thread about the incident here) I decided that my safety more important to me and my family than the risk that my light might pose to any unfortunate oncoming epileptics. After all, the emergency vehicles around here use strobe lights to catch the attention of oncoming traffic, so why shouldn't I?

Because they're huge and also have lights that don't strobe and, although their lights are bright, none of them are blinding. The combined effect is to make the vehicle unmissable, where as a blinding flashing light on a cyclist is infuriating and can maker it /harder/ to see where they are or where they're going.

Also, a commuter on a bike is just another road user where as a public service vehicle should get priority.

Don't get me wrong, I'm all for making ourselves as visible as possible, but flashing ultra bright lights are not helpful.

Keep it on full and point it at the road ten feet ahead - much better for everyone.

There's a reason why a car headlight beam has to be check and align. Nothing is more irritating than having the car behind you with there low beam reflecting off your rearview mirror right into your eyeball. Personally, I feel the same goes with bike light. Nothing is more irritating than seeing stars and pokidots after blinded by the light at the end of the tunnel.

I do run a MS light and the spill is a lot. I have it mounted at the end of my handle bar within finger reach for instant adjustment to be courteous to pedestrian. Normally the light is angle down just to see potholes and glass on the road. The spillage of the light is enough to be seen even at that angle.

I have a single 35w in a homemade housing running the same battery as above, also powering a 110dbl car horn mounted below the light. I don't ride an MUP, only public roads, so I'm not concerned about "too bright". I also keep it aimed on the road far out ahead of me. It lights a pretty large area.

+1! Poorly positioned lights (including helmet lights) are more than just an annoyance, they are dangerous. Once your lights are bright enough to be blinding at night you really should have the common sense to point them down towards the road in front of you, not towards objects at eye-level where you run the risk of blinding an operator of an oncoming vehicle. Remember, you're riding a bike on the street... not mining for coal or spelunking.

Point it at the ground for crying out loud. Your light does not need to be pointed at my eye level. I saw you just fine and so do most motorists.

The problem isn't brightness -- even the hottest bike lights can't do what a single auto headlight can. The problem is where you point that thing.

Well...they can be

This is the real crux of the problem. However, it's only a tiny problem. Look at where we ride our bikes on the road (MUPs are a different issue). We don't ride near the center line but we ride to the right of the passenger's side of the car. The passenger's side light is aimed higher and further down the road than the driver's light and it is much brighter than most bicycle lights. How is a rather weak light further to the right of where a brighter, higher aimed light normal is used, going to blind on-coming traffic? Especially the highly directional lights like LEDs?

LEDs are very bright in the center of the beam and fall off very quickly to the edges. Halogen beams...like most cars have...aren't nearly as bright in the center as an equivalent LED and have more side spill. However, since more light spills to the sides, the localized intensity of the light has to be less thus even halogens as bright as I can make them aren't going to be a significant blinding hazard to on-coming traffic on a roadway.

The way I look at it is that motorists aren't concerned about blinding me, why should I be concerned about blinding them?...not that I could anyway

1) That's a generalization. In the cities where I've commuted, cyclists travel in all lanes therefore their lights should be positioned well otherwise they can blind oncoming traffic.

2) It doesn't matter if a car light is brighter than a bike light. If they both are bright enough to blind someone, then they both should be aimed appropriately. (refer to comments 3 & 4)

3) Part of your response is strictly argumentative and without merit since the driver's side and passenger's side headlights, as a rule, are aimed to the same height and at the same distance from center. That's been a common practice for at least the 30 years that I've been driving as illustrated here: https://www.coolbulbs.com/HID-VISUAL-...-PROCEDURE.pdf


4) Lights are a blinding hazard if they are improperly aimed which is the basis of our concerns... people aiming bright lights at about eye-level. I have a $1.50 9-LED flashlight powered by 3 AAA batteries that can hurt the retinas and cause a blind spot if improperly aimed (remember the helmet light concerns in other posts?) and it's nowhere near as powerful as my MR16 halogen headlight, which I'm sure we can agree isn't as bright as the average car headlight.

All lanes? Most cyclists I see travel outside of the main traffic lanes in an attempt to preserve their third dimension. Yes, they may move over to turn but so do cars. Bicyclist don't ride a significant amount of time next to the center line of a road way...especially at night...where they are going to be a significant blinding hazard to on-coming traffic.

I doubt, highly, that if you really looked at the bicycle traffic in the cities you've ridden in, there aren't a significant number traveling very far from the passenger's wheel track of automobile traffic. (From here on, I'll refer to the passenger's side as the 'right' side of the car. If you live where they drive on the goofy side of the street, you'll just have to make the adjustment in your head.)


Yes, bicycle lights should be aimed appropriately. But where a bicycle light is aimed is hardly as much of an issue as some would make it out to be. If you ride at night for a while, you'll find your lights aimed down where they do you good rather than spraying off into space. Why carry the damned things if they are ineffective?

I was wrong about the right side light being aimed higer. But the overall effect of automobile lamp aiming is that there is more light to the right of the car than the left.

Take a look at step 4 or go really observe the lights on your car. The cut-off for the lamp is to the upper left to keep the glare down for on-coming drivers. The bulk of the light is biased to the right side of the car so the right side...the passenger's side...has more illumination that shines further down the road.


No, your $1.50 LED light can not hurt retinas. Hurt implies damage, usually of a lasting kind. It may cause temporary saturation of the light receptors in the eye but that passes in a matter of seconds. You could stare directly at the center of the light for several minutes and still not be left with any lasting effects. These aren't lasers nor the sun, afterall.

Yes, proper aiming of the lamp is important as I've already said. It just common courtesy and common sense. But it's not something to get our bicycle knickers in a bunch over.

Nice. Really responsible

It's not just poorly positioned lights that are dangerous, it's also flashing front lights. Yes, a flashing light is distracting and eye catching, but in the intervals between flashes the cyclist is /harder/ to see. It just makes knowing where they're going slightly harder, which is not something you want when either party is traveling at speed.

If you are going to quote, quote in context. Note that I said "not that I could anyway".