Peglau criticised the fact that the standard colours of the traffic lights (red, yellow, green) did not provide for road users who were unable to differentiate between colours (10 percent of the total population); and that the lights themselves were too small and too weak when competing against luminous advertising and sunlight. Peglau proposed retaining the three colours while introducing intuitive shapes for each coloured light. This idea received strong support from many sides, but Peglau's plans were doomed by the high costs involved in replacing existing traffic light infrastructure.[3]