What does this sign mean?

• Drivers must stop completely at the bus stop.
• Drivers must yield the right-of-way to buses at bus stops.
  Explanation:

  "This sign indicates that drivers must yield the right-of-way to buses at bus stops. This means that when a bus is pulling out from a bus stop, other vehicles must allow the bus to merge into traffic safely."
• Buses must yield to other vehicles at bus stops.
• Drivers are not allowed to pass buses at bus stops.