What purpose do rub rails serve on a school bus?

Rub rails on a school bus primarily serve to indicate floor and seat levels. They are typically positioned along the sides of the bus at various heights, providing visual cues for passengers, particularly children, regarding where the floor and seat levels are located. This is essential in ensuring safe entry and exit from the bus, as well as helping passengers gauge the height of the steps and the seating area while boarding or disembarking.

This feature is particularly important in a school setting, where younger passengers may not always have a full understanding of spatial awareness. By visually outlining these areas, rub rails contribute to overall safety and help prevent accidents.

Rub rails do not play significant roles in aerodynamics, height clearance indication, or structural reinforcement. While these elements may be relevant to vehicle design in other contexts, the primary function of rub rails on a school bus is to enhance safety by clearly demarcating important spatial areas for its passengers.