Asked in Rules of the Road
When is it necessary to stop before proceeding when you overtake a school bus loading or unloading children?
When the bus is displaying the second half of the eight light
warning (alternately flashing red lights) all traffic proceeding in
both directions of an undivided highway of four or fewer lanes must
stop. If the highway is four or more lanes and is divided (by a
median strip, for instance) only traffic proceeding in the same
direction as the bus must stop. The vehicles must provide at least
10 feet of distance to the bus when stopping. It is illegal to
overtake or pass a bus that is stopped to load children.
In Texas, you must stop 50 feet from a school bus that has it'smovable stop sign(s) extended and alternating red lights flashing. Roads that have a median divider do not require opposing lanes of traffic to stop unless the median has a cross-through where the buss is stopped.