How old are you two? I'm getting the vibe that she's insecure about dating. I'm getting a vivid image of her distancing herself because something's scary about the whole thing. Normally when we hear these push-pull stories on GAF, it's about the one party having read too much into the situation, then when they finally meet, the other retreats, because the person is coming on too strong. It's not really what's happening here. It feels like she's shy and unable to not distance herself. Try to give her some room. If you constantly text her, if you react to her sending you short responses in one of all the days you've been talking, you're going to push her away, because it is like the hand and the shadow. When one retreats, the follows.
Try something new. Try to not initiate stuff. Don't bring up "having been used for free meals", because while it is admirable that you're honest (and I honestly mean that), you're also expecting you opening up about being vulnerable to not just push her away. When you've got a girlfriend, that's when you can open up all you want and she shouldn't run away. However, this is still a sort of mating dance. You want to display yourself as a capable mate. If she doesn't reply that much, just drop the conversation. If you're the one to initialize, try not to. The idea is that when you distance yourself, too, she'll be the one that follows. At that point, she'll feel more invested, and she'll have more to lose, so she won't just get out of the car at the end of the date. Get her to invest, too, that's the idea.
Do that. She will contact you, I can guarantee it. Let her initialize the next date. Then, when you're on that date, you can consider going simply "I really enjoy hanging out with you, but sometimes I get really mixed signals from you, like when you jump out of the car when I've driven you home. Is there something that makes you feel uncomfortable?" There's nothing wrong with talking to her about it, just do it in a very calm manner. Ask because you're wondering if something's bothering her, not from the view that it's bothering you, because if you do, you're inches away from basically saying you deserve more after you've driven her home, and that might make her uncomfortable.
I think you'll find that she's somehow reserved in those situations. Perhaps rather you can say "it feels like you're a bit uncomfortable with the end of the dates. I just want to say that I'll take this as slow as you need to, but it makes me uncomfortable when you leave that abruptly". You're saying you understand her reaction, but that it's not nice for you when it happens. Just don't keep pushing. That'll make her distance herself.