What this story is really about, is sleep deprivation and fatigue. Some commenters in the news stories have taken a "blame the victim" attitude. There are comments to the effect that people ought to know better than to drive when there is danger of falling asleep, and that Beth Jasper was responsible for her own death. Aside from being cruel to the point of sociopathy, most of those types of comments ignore what we know about the science of sleep, as well as the manner in which people make decisions.
First of all, sleep deprivation is cumulative. Miss one or two hours of sleep a few days in a row, and you cannot make it up by one really good night of sleep. In fact, studies have shown it may take longer to recover from several days of sleep deprivation than the total amount of sleep lost in the first place.
For those who expect people to have insight into when they are driving sleepy, I have news. There is a phenomenon called microsleep. It means dozing off for a few seconds at a time, without even being aware of the sleep. Several news programs have done stories on microsleep. Reporters who were filmed dozing off for a few seconds at a time, some while driving, were both startled and frightened at how quickly and easily micorosleep happens. Most of all, how frequently. The video above is a story done by an ABC reporter for Nightline.