What does this sign mean?

• Only emergency vehicles may use this lane.
• All vehicles are allowed to use this lane.
• Only public vehicles such as buses, or passenger vehicles carrying a specified minimum number of passengers, may use this lane.
  Explanation:

  "This sign indicates that only public vehicles, such as buses, or passenger vehicles carrying a specified minimum number of passengers, may use this lane. These lanes are known as High Occupancy Vehicle (HOV) lanes and are designed to encourage carpooling and reduce traffic congestion."
• Only motorcycles may use this lane.