VIDEO: The southbound lanes of Interstate 35W were treated with a brine solution before a deadly 135-car pileup during February’s winter storm, according to a preliminary investigation. The National Transportation Safety Board released its preliminary report on the crash Wednesday. The massive pileup happened on the morning of Feb. 11 on the southbound side of I-35W near Northside Drive, north of downtown. Drivers who were reportedly traveling at a high rate of speed ventured onto slick roads coated with a thin sheet of ice from freezing rain that had fallen overnight and into the early morning hours. Cars, trucks and 18-wheelers collided one after another for a crash scene that stretched for nearly a mile. Six people lost their lives and dozens were injured.