Mystery death of scientist (Yet another scientist has been killed in mysterious circumstances)
Contains info on bridge jumper pushee in Tennesse
If the gasoline could have been smelled inside of the car it would have drawn attention. Something inside the car could have sprayed her (triggered on an event) but could it do sufficient quantity and a fireball quick enough to overtake her to prevent exit (or maybe faulty door locks that she was willing to manage with until she "owned" the car)?
It's all speculation. The only car bomb I can recall from the movies is the one on the radio at the beginning of Casino.
Someone who has seen the different flavors of car "bombs" will be better prepared to look for clues as to just what was done in this instance.
I'm thinking that she may not have even been incapacitated when the fireball torched (so fiercely that she breathed it in, possibly indicating something in the front). I would throw some suspicion on the locks (if she couldn't get out then she would be incapacitated quickly and no one would be the wiser).
I believe that it would be difficult to sustain the car in motion on the highway after placing the body inside. I would think that it would soon be off course.