Not so sure what is hard to understand about factoring in miles driven to asses a companies safety record ? If a company has 2000 trucks it’s fair to say they are probably going to have more accidents than a company that has 10 or 20. Call it a handicap if you will. The list was compiled a number of years ago on Kevin Rutherfords show (Trucking business and beyond) on Sirius xm. When miles driven were factored in fedex actually had a very high safety rating. IE we all get a bad rap. It isn’t just ground drivers involved that is for sure.