P and S endorsements are only added to a CDL upon request and require that drivers take additional knowledge and skills tests.
Employers must do a background check on all potential school bus drivers. Only drivers with clean records can legally drive a school bus. School bus drivers need a Commercial Driver’s License (CDL) with a Passenger (P) and School Bus (S) endorsement before they can legally drive a school bus. The licensing process has two parts: knowledge test and skills test.