Originally Posted by
climber314
Was the RWSL system not operational or just ignored by the crossing aircraft?
"Runway status lights (RWSL) are now operational on runways and taxiways at Washington-Dulles International Airport (IAD).
The fully automated lighting system is being implemented at airports throughout the U.S. as part of a program to help enhance runway safety. The lighting system provides direct runway status information to pilots and surface vehicle operators indicating when it is unsafe to enter, cross, or takeoff from a runway. It requires no input from controllers as it processes information from surveillance systems and then activates runway entrance lights and takeoff hold lights in accordance with the motion and velocity of the detected traffic.
Light fixtures embedded in the pavement are directly visible to pilots and vehicle operators.
The Federal Aviation Administration (FAA) plans to have RWSLs operational at 23 U.S. airports by the end of 2016."
https://www.nbaa.org/ops/safety/runw...es-airport.php
It is obvious that the Sky West and AAL aircraft crossed as directed by the Tower controller and EITHER the RWSL system was not working OR they assumed that the controller's direction overruled the RWSL stop indications. This means that if the RWSL was not working it needs investigation; or, that a new rule needs to be put in place that RWSL indications have a higher priority than clearances from the controller - in a similar way as a TCAS RA must be obeyed regardless of what the controller is directing.