They are not, because we don't have enough data to support escalating it to the watch-list. We have lots of safety issues that concern the board, but they can't all be on the watch-list, because the watch-list is used for those posing the greatest risks or that can do the most to advance transportation safety. We simply don't have the data to date, partly because we've only conducted a few investigations involving buses and trains.
On April 2nd, 2019. See this statement in context.