Originally Posted by
tcasblue
It is interesting to watch them in SFO while holding on 28R/L. They are activated for the cross runway takeoff with the standard red lights but actually extinguish prior to the aircraft rolling on 01L/R reaching the intersection.
The system is designed that way. The timing is such that the controller can clear you for TO or to cross the runway as the traffic goes by and there will be no conflict with the RWSL system.