[crazygringo]

To be fair, the flashing on bicycles is intentional, precisely to make sure you are aware of them, since they're so much smaller and vulnerable, and the light itself is so much smaller than the rear light on a vehicle. It's not just on rentals, it's a standard feature of bicycle rear lights that is there for safety.

[martijnvds]

In the Netherlands, bike lights _must not_ flash. The law very explicitly states that they need to be "always on" (in the dark).

The main reason seems to be that it's hard for others to to gauge your speed when your lights are flashing.

[crazygringo]

Fascinating. I just looked up a bit of research on it, and it seems there are two contradicting phenomena at play. Flashing helps in seeing cyclists further away and helps with visibility generally -- but it also makes it harder to estimate speed and distance.

Apparently, the absolute safest solution is to have two rear lights side-by-side -- one that is always on and one that is always flashing.

It doesn't seem like there's clear data on which is safer if you have to pick only one. Different countries/states have chosen differently.

[exmadscientist]

Flashing on-off and always on aren't the only options. I wish more designers went with flashing bright-dim, because it solves a lot of problems.

I once worked on a device where we were required to blink the Important Safety Light™ on-off. I often glanced at this light out of the corner of my eye, and saw that it was off, so we were Safe™. We were not Safe™: it was just in the off phase of its blink.

I am very glad I never got hurt by trusting that light.

I wanted to blink it bright-dim but was denied by people who said that IEC 61010 required it to blink, and blinking bright-dim isn't blinking. I didn't quite understand that objection.

[crazygringo]

Having a third brightness state feels confusing.

If a safety indicator needs to be visible at a glance, why did it blink at all?

Blinking only works for things that are in your vision and need to be the primary focus.

It seems like blinking to begin with is terrible design for something like this, or else having it be in the corner of your eye is the terrible design decision.

[exmadscientist]

> If a safety indicator needs to be visible at a glance, why did it blink at all?

Beats me! But they've apparently flashed for ages and ages on these things, and somewhere along the line it got standardized.

> It seems like blinking to begin with is terrible design for something like this, or else having it be in the corner of your eye is the terrible design decision.

This is benchtop equipment, not cars, so "corner of your eye" has a little bit different context here. But, yes, I kind of agree.

It is also really important to get this one right since for this particular type of device, conditions are lethal (yes, genuinely lethal, no exaggeration) if you get cavalier with it.

[Y_Y]

This is a strong point. Nobody likes a rapidly flashing light (extra annoying, seems broken, can be hard to differentiate from "on but dim"). Then again if you flash slowly then you'll have some appreiable amount of time when it's off and that can include the entire opportunity you have to look at something.

Ideally (for me) you could have smooth high-low alternation or colour alternation.

(I recognize that something that looks like emergency services, e.g. alternating blue/white may be illegal, and that colour-blindness may limit this approach.)

[arccy]

but also there are so many bikes there already that they didn't need to raise general awareness that much

[Y_Y]

I dunno man, I'm a cyclist, and I live in a big city full of cyclists. I've also used and seen a lot of bike lights in my time. Flashing is often an option, but the default is usually "always on".

Also flashing is really fucking annoying, and I my own experience is that it does notale cyclista more visible or safe. I don't use flashing lights myself, even though I can't see the rear one and eould probably rather be annoying than dead.

[crazygringo]

It seems like it depends a lot on the city/country.

To be clear, I'm talking about rear lights only. The front light is white and always-on so you can see the ground. Plus you can see what's in front of you, so you avoid things, people don't need to avoid you as much.

It's the rear red light that flashes. You yourself don't see the flashing, but it increases visibility so people don't run into you, when you can't see them behind you.

When I'm behind a cyclist with a flashing red rear light, it doesn't bother me. It feels safe. It probably encourages me to keep a little extra distance from them, which is a good thing.

[RandallBrown]

Flashing lights on bicycles are illegal in a lot of places.

If bikes didn't move, a blinking light would be fine. But they do move and it makes it really hard to tell where the bike is in the dark.

[jandrese]

Blinding and dazzling oncoming traffic in the name of safety is outright stupid.

If you are riding a bike and you're lighting up the heads of oncoming riders or pedestrians you are being dangerous and obnoxious. Never shine a flashlight above someone's shoulders at night if you can help it.

[crazygringo]

What are you talking about? Did you mean to reply to a different comment?

Bicycle lights aren't blinding anybody. At least none I've ever seen. They're powered by little batteries usually.

The subject at hand was whether they flash or not. Not their brightness, which I've never heard anybody complain about.

[jandrese]

You definitely don't ride around here if you have not been blinded by a bike headlight. They can blow away your vision from half a mile away easily. I can't even see the trail in front of me without putting my hand up to block the light. I call it the nighttime salute.

They are much worse if they flash. That blinds and disorients. Even after they pass you won't be able to see anything for some time.

[crazygringo]

True, I'm referring to places where there are already car headlights. The bike lamps are so dim by comparison, there's nothing to complain about.

If you're somewhere without any other lighting and your eyes have adjusted to the darkness, then I can understand how they might seem bright. But I'm not really sure what you think the solution is. They're already vastly dimmer than cars, but make them any dimmer and the cyclist won't be able to see the ground and it won't be safe.

[jandrese]

That is still very much not my experiance. I ride on the roads a bit and usually cars are fine, although there are people with aftermarket lights and people who just leave high beams on all the time in heavy traffic. But I've experienced riding down the road with oncoming traffic in the other direction and doing just fine until a bicycle comes and blinds me just like the high intensity high beam guys. They are generally much brigter in terms of light delivered directly to the eyeballs of oncoming traffic. Are you sure people aren't seeing you because your lights are too dim, or because you're making it impossible to see anything around them?

[crazygringo]

Fascinating. I'm honestly quite confused -- most of the bike headlights I see simply run on 2-3 AA or AAA batteries, and it doesn't seem physically possible for them to output the kind of bright light you're talking about. I personally am very careful to angle them downwards, because the entire point is to illuminate the ground in front of me -- if I'm shining in people's eyes, then it's not illuminating the ground. And they're already so weak, you need all the illumination you can get.

E-bike rentals don't have anything adjustable, and where I am, they're quite fixed at illuminating the ground.

Maybe there are people with e-bikes who can draw a lot more power and have higher-powered headlights? Are you talking about e-bikes specifically? But it's just not something I've ever seen. I'm certainly blinded by vehicles while cycling under certain circumstances, but I've never once in my life felt blinded by cyclists or even anywhere close. That's why I'm so confused by what you're describing. When you say "blow away your vision from half a mile away easily", I honestly can't even begin to imagine what you're talking about.

[4ggr0]

while walking i frequently get blinded by eBikes which for some reason decide to point the lamp towards the sky to contact far-away civilizations, or whatever their plan is. happens quite frequent that i have to shield my eyes with a hand because i don't see anything until the eBike is past me.

[MobiusHorizons]

They 100% are. I’m a cyclists in Seattle ride to and from work 4-5 days a week. This time of year it’s dark by 5pm so bike lights are on full force on the home commute. Being dazzled by oncoming bikes happens almost every trip. I absolutely hate it, it’s sometimes even worse than the cars, although car headlights have caught up in awfulness in the last few years. My least favorite type of overly bright bike lights are the blinding and also blinking rear red lights.

People do it for safety, but it doesn’t help. I literally can’t see where you are if you have a bright light shining in my face. The same thing is true if I’m in a car. As long as you have lights I can see you. If your lights are obnoxiously bright and especially if they are blinking you have succeeded in making people want to harm you, not increased your safety. The drivers who aren’t paying attention will not be more likely to see you if you are just a blinding glow of light.

[elric]

> Bicycle lights aren't blinding anybody.

They absolutely are. They suffer from the same phenomenon as car headlights. They're often poorly aimed (at an upwards angle instead of downwards) and have adopted an insanely bright white colour. I frequently yell at other cyclists when they blind me.