Knight-Swift Transportation, the largest U.S. truckload carrier,  has a new CEO, Adam Miller. David Jackson stepped down as chief executive after nine years in the post and has also left the company’s board.

The Wall Street Journal says the company is seeking a path back to profitability in a troubled freight market marked by soft shipping demand.

Knight-Swift has expanded its truckload profile, first with its acquisition of Swift Transportation and then by buying U.S. Xpress last year. But industry experts are watching its smaller less-than-truckload segment, where operating margins are better, and revenue grew rapidly last year.