One-way traffic lanes are RECOMMENDED for use by all vessels travelling between the points involved. They have been designed to aid in the prevention of collisions at the approaches to major harbors and along heavily traveled coastal waters, but are not intended in any way to supersede or to alter the applicable Rules of the Road. Separation zones are intended to separate inbound and outbound traffic and to be free of ship traffic.  Separation zones should not be used except for crossing purposes.  When crossing traffic lanes and separation zones use extreme caution.  The normal Pilot Operating Areas are outlined by trapezoidal magenta bands. A Precautionary Area has been established at Los Angeles - Long Beach.  It is recommended that vessels proceed with caution in this area.