joan brook is the head of the national highway and safety administration. said driver fatigue is the leading cause of many truck driver accidents. >> this is unsafe on the american highways for all of us and most of the people harmed in these crashes are people in cars. >> data shows there were 317,000 police-reported motor vehicle accidents involving large trucks in 2012. nearly more than a thousand of those resulted in fatalitiefata. traveling with him were fellow assistants. mcnair was killed. the others remain in critical condition. anne-marie green, cbs news, new york. >>> cbs news has learned the truck drive has told police he may have dozed off. kevin roper is expected to be arraigned today. the national transportation safety board continues its investigation. >>> coming up on the "morning news," new help for repaining student loans. details in "money watch." >>> plus, charity walk. a michigan teenager carries a younger brother on his back on a long journey. this is the "cbs morning news." want a fiber that's clearly healthy? benefiber is clear, tast