Traffic lights at night safe navigation of the ship

To ensure safe navigation of ships in the night some beacon mounted on a class of traffic lights. It sends a predetermined color and flash lights at night frequency, to reach a predetermined irradiation angle and visibility distance.
beacon lights for trucks fixed beacon, four kinds of light buoys, lightships and lighthouses. Fixed beacon and light buoy structure is relatively simple, the light system Serve on Libiao and buoys. Lightship was anchored at sea can not be building the lighthouse place warning beacons for navigation and use.