> Jennifer Homendy, chairwoman of the National Transportation Safety Board, said at a news conference Tuesday that the airport uses a safety system called ASDE-X to track surface movements of aircraft and vehicles.
> "ASDE-X did not generate an alert due to the close proximity of vehicles merging and unmerging near the runway, resulting in the inability to create a track of high confidence,” Homendy read from an analysis of the system’s performance.
https://www.nbcnews.com/news/us-news/investigators-search-an...
> Jennifer Homendy, chairwoman of the National Transportation Safety Board, said at a news conference Tuesday that the airport uses a safety system called ASDE-X to track surface movements of aircraft and vehicles.
> "ASDE-X did not generate an alert due to the close proximity of vehicles merging and unmerging near the runway, resulting in the inability to create a track of high confidence,” Homendy read from an analysis of the system’s performance.