Lots of really good advice there, johntalin.
Elbow strikes are definitely effective. I once knocked a guy unconscious with two elbow strikes ... he was wearing a football helmet covered in thick padding at the time. The most important thing to remember, however, is that if you are going to hit someone you need to
hit him. Not tap him, not pull back at the last second ... use all your strength and force your hand, elbow, knee, whatever
through him. Also, don't punch with your fists. The odds are very high that you'll hit something harder than your knuckles and do more harm to yourself than your attacker.
Trunk of car: first, a lot of modern cars have a little lever you can pull that will open the trunk from the inside. Second, I wouldn't get in the trunk to begin with. A lot of johntalin's advice refers to what we call "crime scene two," the place the BG is going to bring you after he's abducted you. Crime scene two is always secluded and safe for the BG. You are in much more danger at crime scene 2. If you're going to fight, if you're going to resist, do it at crime scene 1 (where the abduction is happening).
While I'm not overly fond of their politics and their subtle "all men are evil" approach, Model Mugging is probably the best training program out there for teaching women to defend themselves against aggressors. The program began when a karate black belt was raped and badly beaten, forcing her friends and teachers to rethink their approach to self defense. They now call it "Impact" and you can
see a list of current chapters here.
My final comment: though most of these gems of advice are directed at women, men are idiots if they ignore them. Being aware of your surroundings and avoid violent conflict is a much better way to get home at night. You might think there's only one BG trying to mug you, but in fact his accomplice is guaranteed to be right around the corner. One guy with a pocket knife can permanently disable or even kill you without much effort or training.
Stay safe!