School Bus Signs - Under the Road Vehicles Lighting (Amendment) Regulations 1994, buses and coaches used for journeys to and from school are required to display distinctive retro-reflective yellow school bus signs fitted to the front and rear of the bus (Scottish Executive 2003). Specifically, signs at the front of the vehicle must be at least 250mm x 250mm with the black border of not more than 20mm wide and at the rear of the vehicle at least 400mm x 400mm with a black border of not more than 30mm (Fawcett and Croner 1993). Each has a silhouette of two children in black on a yellow reflective background.