Phoenix, AZ-Based Knight-Swift Transportation Holdings 4Q 2017 Operating Income Up 314% Over the 4Q 2016, Pretax Income Up 294% and Net Income Up an Off-the-Charts 19 TIMES or Up $425 Mil, With the Latter Buoyed By an Income Tax Expense Reduction of $364 Mil in the 4Q 2017, Mostly Related To Tax Debt Forgiveness in the Trump Bill