When approaching a stopped school bus with its red lights flashing, you must come to a complete stop and proceed when

On all undivided highways (without a median), traffic in both directions must stop for a stopped school bus that has its red lights flashing. You may not proceed until the bus resumes motion, or signaled by the school bus driver to proceed or the visual signals are no longer actuated. [School Bus Rules; Chapter VI Traffic Laws and Rules of the Road; State of West Virginia Driver's Licensing Handbook]