Flashing strobe headlights: estimating distance

MichaelW

Yesterday I was riding through a very dark lane when I saw two sets of flashing strobe lights. I couldn't estimate the distance and I couldn't be sure if it was a bike or how many there were. I thought it may be 100m away but they were only 30m.
If you have a front LED lamp on strobe, you may want to consider how much information you are giving to drivers. Steady lights are far easier to use for distance estimation. Use strobes in daylight and solid lights at night.
If you have 2 lights, keep one on solid. 2 strobes flashing out of sync is really hypnotic.

de_sisti

Surely, if you're worried about being able to judge the distance, wouldn't it be a good idea
to slow down/come to a standstill, until they've gone past you?

deadfall

Also point the damn lights downwards, I'm getting sick of constantly being blinded the guy I see quite often on a well lit cycle path with high power lights aimed at eye height. I know I'm not the only one, a few other cyclists have mentioned him to me.

Mr Will

Depends on the location. In a street-lit area flashing is good for attracting attention. On a dark country lane you become harder to spot and less able to see.

de_sisti

Mr Will wrote:

...On a dark country lane you become harder to spot and less able to see.

Do you mean it makes one become invisible?

tmg

I think the OP does have a point, with the best intentions those that use them are trying to protect there own safety but sometimes they can have the opposite impact. I witnessed one a couple of weeks ago where a guy was coming down a hill through a small village approaching a t junction, him being on the main road having right of way, he had a front light on flash mode, a woman rolled up to the junction to turn left and made a quick judgment it was OK to pull out, I can only guess that she saw the flashing light (I was further away from the junction in the opposite direction and could see it clearly) and assumed it was an indicator from a car behind the guy on the bike and decided to go, the guy on the bike had to pull on the brakes pretty sharpish to avoid hitting the side of her car. I think if your going to use them then two lights with one constant and one flashing would be the safest option

HoHoHoBlueGiant

I agree with the poster who thinks having a flashing front light has the opposite effect to the intended.

Cars always seemed to pull out on me when I had my front light on 'flash'. I think part of this is that a flashing light does scream 'cyclist' which drivers subconciously think will be travelling 'slow', so 'enough time to pull out'. I now just run one solid bright light on the front, I think it's more likely to make motorists think 'motorbike' i.e. 'fast, best wait'.

I use the opposite theory for rear lights though. I have a flasher and a solid light as I don't want them thinking I'm faster than I am and rear ending me! Flasher to be seen, solid to help with judging my distance from them.

I've absolutely no proof on all this obviously but haven't had an incident on a car driver pulling out on me at a junction for quite a while.

Bozman

I nearly totalled someone whose only light source was a strobe light, should be law to have a fixed beam.
Strobes seem ok on quiet roads but as soon as you put them in busy traffic they disappear,i only missed the guy because i double checked before i pulled out in to traffic, god knows how i missed him but it was his lucky day, the guy had a cheap flashing light with 3 leds and no fluorescent gear cycling on a busy A road, idiot.

AchillesLeftKnee

Maybe I'm a bit odd in this respect, but I find riding with flashing fronts to be quite barf-inducing, especially on unlit roads.

APIII

Flashing front lights are idiotic. Shouldnt they be illegal?

redvee

APIII wrote:

Flashing front lights are idiotic. Shouldnt they be illegal?

I was under the impression that to comply with BS6102/3 you could only use a flashing light with a solid one but it would appear you can use them solo

BS6102/3 wrote:

One is required, showing a white light, positioned centrally or offside, up to 1500mm from the ground, aligned towards and visible from the front. If capable of emitting a steady light it must be marked as conforming to BS6102/3 or an equivalent EC standard. If capable of emitting only a flashing light, it must emit at least 4 candela.

diy

Its well documented that flashing lights and very bright lights cause this problem. There used to be a fashion for motorcyclists to ride main beam when filtering. Partly due to stupid homogenisation rules preventing two front headlights on motobikes to avoid them looking like a car in the distance.

The bright/strobe light reduces our ability see contrast detail. This impacts our ability to judge movement, which impacts our ability judge speed/distance.

"Tactical" lights have a strobe function specifically for this purpose. i.e. to disorientate the pray/enemy.

Laird_Attwood

diy wrote:

Its well documented that flashing lights and very bright lights cause this problem. There used to be a fashion for motorcyclists to ride main beam when filtering. Partly due to stupid homogenisation rules preventing two front headlights on motobikes to avoid them looking like a car in the distance.

There have been many motorcycles for many years that have had 2 headlights (Yamaha, Ducati, Cagiva, BMW, Honda are just a few who have produced them)

de_sisti

diy wrote:

Its well documented that flashing lights and very bright lights cause this problem.

Where?

diy wrote:

The bright/strobe light reduces our ability see contrast detail. This impacts our ability to judge movement, which impacts our ability judge speed/distance.

Can you quote your source?

diy

Try googling "effect of low contrast on speed judgement". Lots of stuff from NASA etc. A lot of sports bikes have one for dip and the other for main. Mot rules say both light must do both functions or one function per light. My old 02 sprint for example needed a relay mod from factory to power the second light. My 08 sprint has twin dip and separate main beam.

PlymouthSam

deadfall wrote:

Also point the damn lights downwards, I'm getting sick of constantly being blinded the guy I see quite often on a well lit cycle path with high power lights aimed at eye height. I know I'm not the only one, a few other cyclists have mentioned him to me.

Tell him next time ? 8)

de_sisti

Why up the ante by telling him and possibly provoking a fight? Just choose a different route.
That way, you know you won't have to meet him on your ride. If you do decide to confront
him, make sure you can have him.

deadfall

De Sisti wrote:

Why up the ante by telling him and possibly provoking a fight? Just choose a different route.
That way, you know you won't have to meet him on your ride. If you do decide to confront
him, make sure you can have him.

I'm usually more interested in getting home than getting in a fight, last thing I need after a day in the office.

PlymouthSam

De Sisti wrote:

Why up the ante by telling him and possibly provoking a fight? Just choose a different route.
That way, you know you won't have to meet him on your ride. If you do decide to confront
him, make sure you can have him.

There's nothing wrong with a polite, are you aware that your front light is a tad bright. Id rather be told if i was unaware,

El Zomba

I recently bought a torch off Dealextreme as a replacement front light. I was out on a ride last week and put the strobe on as it was starting to get a bit dusky, but not dark enough for a solid beam. It turns out that the strobe on it is absolutely vicious; very fast and very bright, so I made sure it was dipped so as not to dazzle anyone oncoming and continued on. About half a mile up the road I caught up to someone riding a horse. Even with the light at a dipped angle, the reflection of the strobe off windows and whatnot was bright and fast enough to upset the horse and get it flailing about . I quickly turned the light off and appologised to the rider once the horse had calmed down. To her credit, she was very polite about the whole thing. I'll not use the strobe again after that; it'll do someone an injury.

veronese68

I go with one static and one flashing front and back on lit roads. When I go through the park I turn off the front flasher as it's just distracting.

diy

@el zomba - the strobe on a "tactical" light such as I am guessing you bought from DX (e.g. 50xb etc) is designed to disorient and reduce the risk of return fire. It should not be confused with a flashing light. Its a strobe. The primary purpose of these lights is mounted below the barrel of a gun for military/hunting uses.

You can adjust the frequency on the strobe by soldering the wires on the driver differently as some drivers are multi-mode and can be adjusted between 1, 3, 5 mode etc with different flash/strobe options. However most of the lights need a driver upgrade to do this.