Which piece of equipment is not required aboard a school bus?

A public address (PA) system is not a requirement on a school bus. The primary focus for school bus safety and functionality is on equipment that enhances emergency communication, provides adequate safety measures, and supports the welfare of the passengers.

While a two-way radio is important for communication with dispatch or authorities in case of emergencies, and both a fire extinguisher and a first aid kit are mandated for ensuring the safety and health of students during transit, the PA system is not considered essential for the basic safe operation of a school bus. It can be useful for making announcements or providing information, but it does not directly contribute to the maintenance of safety or emergency readiness in the same manner as the other required equipment.