Question:

You see a school bus with its red lights flashing and stop arm extended ahead. What must you do?

A You must come to a complete stop regardless of which direction you are traveling.

Explaination

Drivers traveling in either direction must stop before reaching a school bus with its red flashing lights switched on. Drivers cannot proceed until the flashing lights are turned off and the stop arm is retracted. [Red Lights, Stopping for School Buses, Traffic Control Laws, Section Four - Rules of the Road, Delaware Driver Manual]