How do vehicles drive in the passing lane?

• Slower vehicles move into the passing lane to the right, permitting other vehicles to pass safely in the left lane.
  Explanation:

  "Slower vehicles move into the passing lane to the right, permitting other vehicles to pass safely in the left lane."
• Slower vehicles move into the passing lane to the left, permitting other vehicles to pass safely in the right lane.
• Faster vehicles move into the passing lane to the right, permitting slower vehicles to pass safely in the left lane.
• Faster vehicles move into the passing lane to the left, permitting other vehicles to pass safely in the right lane.