Cycle Safety Campaign Transport for London

Only a tiny fraction of all the information going into your brain enters your consciousness. People often fail to see a change in their surroundings because their attention is elsewhere. This phenomenon is known as "change blindness". Even stranger, if you are concentrating on something, you can become blind to other events that you would normally notice. This "inattention blindness" is possibly the reason why motorists collide with cyclists.
Just as it is important for road users to keep an eye out for cyclists, cyclists must also take steps to ensure they are seen by motorists.See this add.