Hi L.,
My son was the same way, and long car rides were monstrous for me. Do you have an infant seat that snaps into a base in your car? If so, does your daughter cry as soon as you put her in the infant seat, or only after she's in the car? We had an infant seat, and my son was fine in it, until we put him in the car. I think he hated not seeing us. When he was a year old, we turned him around (so he faced us) and he was fine. But if your daughter cries as soon as you put her in the seat, maybe the seat itself is uncomfortable.
We played fun music, and that helped a little bit. We mostly listened to Ralph Covert. He's a really great children's musician. The only other things I can suggest are frequent breaks, and as a last resort - ignore the screaming. I know it's hard, but as long as she's healthy and safe, she'll be fine. Good luck!