“The Toyota Way recognizes that visual management complements humans because we are visually, tactilely, and audibly oriented. And the best visual indicators are right at the worksite, where they can jump out at you and clearly indicate by sound, sight, and fell the standard and any deviation from the standard. A well-developed visual control system increases productivity, reduces defects and mistakes, helps meet deadlines, facilitates communication, improves safety, lowers costs, and generally gives the workers more control over their environment.” 

The Toyota Way 2nd Edition by Jeffrey K. Liker (McGraw Hill, 2021) p. 157.