1) speed was mostly around 70mph, too fast for a heavy vehicle.
2) the rv shouldn't have been camping in the far left lane for that long. from their voices, they were to make a left turn at a fork ahead, however they should have been in the 2nd lane from the left.
3) heard they said "whoa" when they saw the box dropped out of the pickup, but the driver didn't slow the rv down quickly that he should have.
a lot of lessons to be learned. for a car driver, remember one thing - don't cut into a heavy vehicle lane without ample space behind you; be aware, those are heavy they can't stop as quickly as a small car can... be safe on the road!