How many signs that read "School Bus" must be displayed on a school bus?

A school bus is required to display two "School Bus" signs, one at the front and one at the rear. This regulation is designed to enhance the visibility of the bus, alerting other drivers to the presence of a school bus and the potential for children boarding or disembarking. The front sign ensures that vehicles approaching from the front recognize it as a school bus well in advance, while the rear sign serves the same purpose for traffic coming from behind. This dual-sign requirement significantly improves safety by increasing the likelihood that drivers will slow down and exercise caution when they see a school bus, especially in residential or school zones where children may be nearby.