Question: Hi Mark Do you know what makes us not be able to see bikes on the road when they r coming towards us. what may effect our site and is there anything our parents can do to be more able to see the bikes. thanks

Mark Hill answered on 21 Mar 2011:

Hello Troyboy,

You have certainly come up with some good questions. This is no exception and is on a subject that I am really interested in. Are you ready for this. I will try and keep it short(ish).

These collisions are known a LBFTS (Looked but failed to see) events.

Two issues are involved here; how the eye and brain work, and conspicuity.

First (and more complicated) let us consider the human eye and dispel ideas that we have of it.

One important fact is that the eye is not a camera, but a data collection device. Although it has incredible resolution, equal to about 123 megapixels, it video streams information to our brains, but in a series of eye flickers, known as saccades.

Let us go back to our very primitive roots, as early humans. Our eyes had to perform a very essential and protective function to allow our brains to answer one major question – ‘Is whatever is in front of me something that I need to run away from, or can I catch it and eat it?’

Our eyes see scenes in a different way than just as a picture of a location, such as a road junction. The focal vision of the human eye, the area in focus when we look at something, is an area only about 5 degrees wide. As we progressively move away from that area, so the image we see becomes more blurred.

Our brains are therefore programmed to quickly make out the outline of an object, then focus on the centre of it, for more information on what to do. This takes time, so, by experience of having been at a location before, we have a map that we put onto that situation, to cut short the time that we spend checking out a familiar junction before acting. These plans, or schemas (schemata) really assist us in speeding up decisions.

However, our brains apply these plans with the more commonly seen vehicles in that plan – cars and such like. There are far fewer motorcycles than cars.

So, at our junction, we have eyes that ‘snapshot’ outlines and feed data into our brains, which apply general plans with commonly found objects…
…not motorcycles.

Therefore, this offers an explanation of why the phrases ‘He was there to be seen’ and ‘He looked but failed to see’ the motorcyclist – probably because of schema, or brain plans – are not necessarily right.

Now for the last bit, which is less in-depth.

Contrast is more important in being seen, than bright colours alone, although a jacket that is not only high visibility, but also has reflective tape works well. If it is a yellow jacket, then it may not be so visible with a hedge row for a background, but the same colour may be very visible with a dark background. Full length sleeves give shape and movement to the wearer. A flashing cycle lamp is also quite effective. This also falls within the foveal 5 degree field of focus as well.

I hope that this answers your question. A lot of work has been completed on this subject. There are also a lot of on-going projects that are also looking at this.

Thank you for your question. Keep safe.

Mark