The new system is designed to overcome a natural “filter” in the brain that prevents regularly varying light signals from reaching the part of the cortex that processes visual signals. This filter helps the brain to ignore regular or continuous signals and, during sleep, it minimises disturbing stimuli.

But irregular impulses of light can circumvent the filter function. The brain is unable to escape the stimulus of random light signals, even if the flickering continues for extended periods.

Werma’s developers have exploited this phenomenon in their new signalling system (above). As part of their development programme, they asked volunteers to judge a series of different light signals to determine which was the most eye-catching.

Based on this research, they have come up with a microprocessor-based signalling system that generates randomly varying light signals using LEDs (light-emitting diodes). The “agitated” character of the light is said to be extremely effective at drawing the attention of anyone nearby, even when it is seen out of the corner on an eye.

LEDs are capable of flickering at much higher frequencies than conventional xenon flashing systems. They are also resistant to vibration and shocks, have long operating lives and require little energy.

Werma says that its “enhanced visibility system” (EVS) will be especially suitable for signalling acute conditions requiring immediate action.