EE was pushing pile of dirt with the D8T dozer, he had his coat hanging in the back of dozer which created a blind spot, he went into reverse and backed up about 10 feet, when he back up he didn't see other ee coming in the A40D hual truck with a load of dirt to unload, he backed up into the haul truck, which caused the tracks of the dozer, to collide with front end truck.