Random flashing is impossible to ignore

. The Enhanced Visibility System (EVS) has been developed by Werma Signaltechnik and uses electronics to flash an LED light several times as second but in a random pattern. The human brain is able to ignore a repetitive flash, so the company’s R&D department sought to find a pattern that could not be ignored. This included asking human test candidates to decide which, among various on-off patterns, was the most eye-catching. The tests showed that a completely random pattern was the most effective, so this is supplied to the LEDs in the EVS by a microprocessor. Because the sequence is random, and below 5Hz, it is not liable to trigger photosensitive epilepsy in people suffering from this condition – as this usually happens with regular flashes in 5-30 Hz range. According to Simon Adams, managing director of Werma UK: “We have been advised that we do not have to supply a health warning.”