Saw - but almost didn't see...

[The Spin Doctor]

...a motorcycle with a tiny 'letterbox' style LED headlight.

Conditions clear evening, twilight... bike coming from my right as I was waiting to pull out of a turning to turn right. Classic SMIDSY territory. The junction's already difficult enough because there's a bus stop right opposite the end of the junction, and a pedestrian crossing outside the tube station to the right, sitting on top of a bridge just where the road bends around to the right too. With railings topped with flower baskets and a e-bike / e-scooter park behind the railings on the pavement, the view to the right is tricky at best.

I spotted the two cars but I almost missed the bike between them.

The tiny LED headlight was on, but was so small as to be totally ineffective as a light to help me see the bike. It didn't help that the bike was a kind of gunmetal grew with a rider with dark kit on.

[Cousin Jack]

I liked the 'road presence' of the VFR. 2 big 55w halogens were fairly easy to spot.

The CB500 has a small LED headlght which is easy to miss, so I have added 2 cheap LED spots. They do little to add extra light in the dark, but they make the front view of the bike much more noticeable. And mine is orange too.

[Dodgy69]

Small can be bright...

[Horse]

Small can be bright...

If it's a headlamp, on 'dip', then it shouldn't be aimed at other road users.

[Cousin Jack]

Something I read many years ago, conspicuity is a mixture of brightness AND the angle subtended at the retina, ie big is good. IIRC it was research into rear lights, but I imagine it is valid for all lights.

[porter_jamie]

I remember being nearly caught out by twin round headlights on a bike probably a Yamaha. It looked at this particular junction like a car further away. Luckily something made me pause. Maybe one big round one is better for that? I dunno.

[Horse]

Many things, including:

Contrast against the background, whether brightness or colour. Not always 'be brighter', for example the 'high conspicuity' black paint scheme used for some aircraft.



Size is important, in particular, for detecting looming - how far away something is and how fast it is approaching.



Movement attracts attention. Lack of movement relative to the background is bad, so use Z Line or SIAM weave when approaching potentially encroaching vehicles.

[NB dragonflies use this trick when hunting - but in reverse. They move relative to their prey to maintain a constant position against the background whilst moving closer]



Combine a couple of things and you get the 'constant heading, constant speed' / 'onstant bearing, decreasing range' problem where, unless on a parallel course, you will collide.




However ...
Being seen isn't being understood.

[The Spin Doctor]

Small can be bright...

Bright does not equal 'conspicuous'.

[The Spin Doctor]

I liked the 'road presence' of the VFR. 2 big 55w halogens were fairly easy to spot.

The CB500 has a small LED headlght which is easy to miss, so I have added 2 cheap LED spots. They do little to add extra light in the dark, but they make the front view of the bike much more noticeable. And mine is orange too.

The surface area of the headlight helps. Brightness isn't the key factor - the 'dim dip' headlights of the 80s was a response to that.

The 'triangle of lights' has some benefits, and making the bike distinct by using a different coloured light in a sea of white lights is a sound idea https://scienceofbeingseen.org/conclusi ... ould-work/

[The Spin Doctor]

Small can be bright...

If it's a headlamp, on 'dip', then it shouldn't be aimed at other road users.

And modern, brighter LEDS have made things worse - the beam is more tightly focused down to the road surface to prevent dazzle... which of course only works on the flat, not when a car is coming over a crest or hits a speed bump.

[The Spin Doctor]

Something I read many years ago, conspicuity is a mixture of brightness AND the angle subtended at the retina, ie big is good. IIRC it was research into rear lights, but I imagine it is valid for all lights.

I think that was Malcolm Newell, and his conclusion resulted in the rear light on the Quasar.

[The Spin Doctor]

I remember being nearly caught out by twin round headlights on a bike probably a Yamaha. It looked at this particular junction like a car further away. Luckily something made me pause. Maybe one big round one is better for that? I dunno.

Been there, done that... one of the very first R1s I ever saw... dull, winter day with the bike approaching around a slight curve against the background of a dark hedge... as the angle changed the lights opened up and appeared to be a car a good distance off...

I started to pull out then stopped about halfway into the lane when I realised the lateral / forward motion wasn't right. The rider didn't slow down a jot but found time to give me the finger as he shot past.

[iansoady]

The surface area of the headlight helps. Brightness isn't the key factor - the 'dim dip' headlights of the 80s was a response to that.

Yes, I always thought they were quite a good idea. A couple of cars I had in the period also had relays that dimmed the brake lights when the vehicle lights were on which again seemed a good plan.

[Horse]

Something I read many years ago, conspicuity is a mixture of brightness AND the angle subtended at the retina, ie big is good. IIRC it was research into rear lights, but I imagine it is valid for all lights.

I think that was Malcolm Newell, and his conclusion resulted in the rear light on the Quasar.

And one of the reasons why emergency vehicles often park 'angled' at incidents. It's also a prompt to approaching drivers that the vehicle is stopped

[Cousin Jack]

Something I read many years ago, conspicuity is a mixture of brightness AND the angle subtended at the retina, ie big is good. IIRC it was research into rear lights, but I imagine it is valid for all lights.

I think that was Malcolm Newell, and his conclusion resulted in the rear light on the Quasar.

It was about rear fog lights when they first became a thing, mainly as bolt ons.. I bought big ones, rather than smaller but probably brighter ones. I also really hate the tiny indicators that are in fashion on bikes.

[Dodgy69]

Maybe these weird small headlights work better in daylight.

[Horse]

Maybe these weird small headlights work better in daylight.

If it's anything like car design, they're a styling fad which is enabled by the flexibility offered by LED technology.

[The Spin Doctor]

Maybe these weird small headlights work better in daylight.

Highly unlikely.

Research back in the early 70s at the TRRL determined that the best pattern for a day riding light was a relatively low intensity bulb (IIRC they plumped for 10w - not even as bright as an indicator bulb) and a lens that spread the light left and right as well as up and down, so that pretty much wherever you stood in regard to the front of the machine SOME light reached you. That's a very different pattern to a tightly focused low beam.

It's no coincidence that police motorcycles had a single DRL bolted to the fairing for years and years.

[Horse]

Research back in the early 70s at the TRRL

Have a look for the 2012(?) TRL review report on conspicuity measures. There's a picture of the TRRL 'ESM' with a prototype DRL (and the astounding 'crash pad' airbag precursor).

It's no coincidence that police motorcycles had a single DRL bolted to the fairing for years and years.

That looked like a Joe Lucas fog lamp ...



I think this pic is from that too.

[Scootabout]

Oh dear. The V85TT has a bright, letter-box-like ('Eagle') DRL, twin headlights, and small indicators.
I try not to ever assume I'll be seen, though.