The nights are drawing in. In a few weeks the clocks will go back and it will be dark as the Cyclologist leaves his ivory tower to pedal his way home. Needless to say the Cyclologist knows the law and his bicycle is fitted with lights front and rear, a nice hub dynamo for the front and a bright LED light on the back. But this year I have been a bit more adventurous.

My children are reaching that age where they ride to various activities, many of them in the evening so in a fit of parental enthusiasm I found a cheap on-line supplier and we all now have EN-something or other certified bright reflective vests with fancy stripes and a colour scheme a chemist would give his right arm for.

"Be Safe, Be Seen" ran the campaign from the Department of Transport, encouraging the wearing of bright and reflective clothing. But last time I checked I was most certainly visible. In fact, had I become invisible I would have been most surprised. And all that is then needed to be seen is for someone to look at you. And distinguish you from the background.

And this is where I am coming to believe that retro-reflectives have been the biggest failing in road safety in the modern era. And to see why we need to delve a little bit into the physics. Retro-reflectives are a fantastic bit of design. They take the light shone on them and send it straight back in the direction from which it came. Normal surfaces spread any light in every direction. So if you are next to the light, the reflectives appear very bright and everything else appears much darker. The further away the object, the greater the effect.

We've all seen it, that winding line of cats eyes down the middle of the road. The hazard signs warning us in plenty of time as we approach a bend. But then take a closer look. Like having a torch shone in your eyes, you saw nothing of the road, nothing of the bend, just the reflectives. Everything else is lost in the gloom, in the dark voids between the dazzling lights. But that is OK. We know where the road is so we can drive faster, pay less attention, drive on the bits we cannot see to be occupied rather than those we can actually see to be clear.