San Diego, CA
The Federal Aviation Administration (FAA) operates a prototype Runway Status Lights (RWSL) system at SAN.
Runway Status Lights, indicate when a runway is unsafe to enter, cross, or take-off through the use of in-pavement red lights installed only at selected intersections and runways as described below.
RWSL conveys the runway occupancy status, indicating when a runway is unsafe to enter through the use of red in-pavement warning Runway Entrance Lights (RELs) and when it is unsafe to take off through the use of red in-pavement warning Takeoff Hold Lights (THLs).
The RELs are a series of red lights, typically 6, 7 or up to 20+ in-pavement lights spaced evenly along the taxiway centerline from the taxiway hold line to the runway edge. One REL is placed just before the hold line and one REL is placed near the runway centerline. All RELs are directed toward the runway hold line and are oriented to be visible only to pilots and vehicle operators entering or crossing the runway from that location.
RELs are operational at the following intersections at SAN:
Runway 9/27
Taxiways B1, B6, B10, C1, C2, C6
When operating at airports with RWSL, pilots will operate with the transponder "On" when departing the gate or parking area until arrival at the gate or parking area. This ensures interaction with the FAA surveillance systems which provide information to the RWSL system.
Runway Status Lights indicate runway status only. They do not substitute for an ATC clearance. Pilots are still required to receive an ATC clearance as they normally would for any operation on the runway.
Pilots are encouraged to learn more about the RWSL system at
http://www.faa.gov/air_traffic/technology/rwsl/