My (most recent) safety issue is how trailers are loaded backwards. Meaning loaded tail heavy. Recently I had a lead that was 6k heavier on tail vs the nose paired with a rear trailer that had a heavier nose then the lead. Example weights starting at axle 2 13k, 19k, 15k, 12k. It didn't feel right pulling it around the yard and when i went back into dispatch I was given crap and they would not put it to the dock. I was told if all axles are under 20k then it's legal. They did eventually give me another lead trailer and left this lead to pawn on some unsuspecting driver. I called safety and as told they were correct the under 20k despite the safety hard ...is safe and legal in their eyes. BTW i've found I get better fuel mileage when the trailers are loaded correctly.