It could be a case where it was someone known to her (friend/someone she had dated or was dating), but without a body, it's never been able to be proved. If the person was never officially named a suspect (and certainly that's never been annouced publicly), then that would definitely be a reason more info has never been released.
Her family did give DNA and presumably reported her missing, as she's in the databases and online. If they suspected someone she knew did it, but it's never been able to be proven, then I can see them not seeing the point of further publicity, then or in more recent years. Both her siblings are deceased now, and neither had children. I'm sure they hoped her body would be found at some point.
Some families aren't as good at getting media attention as regards their missing loved one, or have things going on in their lives that prevent them from being able to get their family member's story out there. Or maybe it was just too painful and they had to move on. At the time, it's hard to say how much attention her being missing would have gotten. In today's world, I think if had been publicized as a cold case story, it would have gotten more attention by now. It's possible, too, it was the decision of LE at the time and today, to not reveal details publicly, perhaps to better identify a perpetrator-a details only they would know kind of thing. That definitely happens.
Someone she knew could have abandoned her car on the interstate to throw off an investigation into her death. They may have had someone they knew following in another vehicle, for example. Or maybe they hitchhiked from somewhere nearby, after they left her vehicle. It would be doable. Perhaps it was a stranger to Jennifer that did this, though. In that case, maybe she had car trouble and trusted the wrong person, or someone pretended they were LE and got her to pull over.
If it's almost certainly a stranger to Jennifer that did this, I do think that LE should probably have released more info/maybe asking for anyone with further info to come forward. And in that case, I do wonder why her family didn't put her story out there more, unless they were told LE was keeping the details to themselves to be better identify a perpetrator. It could be it was something her family had to leave it to LE to solve, as they had to put it behind them to continue on with life. It was the second tragedy in the family after her mother's early death.
