What does this sign mean?

• It indicates a prohibited action.
• It provides a warning about potential hazards.
• It indicates a permitted action.
  Explanation:

  "A green circle on a white background is a regulatory sign that indicates a permitted action. It tells drivers what they are allowed to do in that area. For example, it might indicate that a certain maneuver, like turning left or right, is permitted."
• It gives directions to the nearest highway.