Once all students are accounted for after an evacuation, what should the driver do regarding the scene itself?

AAMVA CDL Manual, Section 10.3.2 (Evacuation Procedures – General Procedures), p. 10-7

An evacuated bus sitting in a travel lane or near a rail crossing remains a hazard to passing traffic and trains even after students are safe. Setting out warning devices protects both the students and anyone else approaching the scene.