The Federal Aviation Administration (FAA) is conducting a research and development project to determine the operational suitability of a system of runway status lights (RWSL) in the National Airspace System (NAS). RWSL is designed as an airport surface safety system to reduce runway incursions. The RWSL system is being design to be a FAA owned and maintained system at larger airports. The FAA Advisory Circulars and Engineering Brief will be used to specify the system requirements for equipment and installation. The purpose of this Engineering Brief is to keep a current specification of the system until a final version is affirmed and included in a future version of AC 150/5340-30. This engineering brief defines the in-pavement lighting configurations for two components of a RWSL system. This EB-64D cancels EB-64C.