Somebody dropped the ball bigtime with the design or something is seriously wrong with the equipment.......you should NEVER maintain a green light headed toward a RR crossing as the crossing arms are falling and the RR signals are flashing.
As soon as the RR crossing gets the notification that the train is coming and generally BEFORE the arms start coming down and at THE SAME TIME as the RR lights begin flashng, the vehicular traffic signal controller should immediately go into "RR premption mode" and display a yellow then red going toward the RR tracks to keep traffic from trying to cross the tracks. There is also usually a far side set of signals NOT VISIBLE to approaching traffic that gives a green signal to cars on the tracks to clear them off the tracks.
I can't see such a setup right off but I'd say its a VERY poor design and an extreme liability to the party responsible for the design and maintenance of the traffic signals. It makes no difference if the driver of the car hit was negligent, it IS a bad design even if there was no traffic signal preemption circuitry malfunction.
EDITED 1/11 @ 1210 CDT: Added image of issue for clarity