My DD2 use to cry all the time in the car seat until I was finally able to turn it around. Basically if I was driving I would pull over give her a comfort BF and put her back in. I put toys in with her and tried a number of things but I think she honestly just wanted to see me. When my DH would drive I would sit in the back with her. I use to carry my DD around ALL the time and co-sleep with her too. Sometimes in the car she would cry and fall asleep, other times she'd cry so much that I had no choice but to pull-over and calm her down. I would play relaxing music and try to talk to her, sometimes it would work and other times nothing I did worked and well I just always pulled over to calm her down. I mean now looking back it didn't seem like such a big deal, it was only for a short time, but I think it did prevent me from going out as much but i think once she was 6 months or less I turned the car seat around which really helped.