How can I make my dog not so afraid of car rides?

She is almost a year old and is still deathly afraid of car rides. She is in the car almost every day, either to my boyfriend's house or the dog park. I thought she would get used to it over time but she hasn't. When I open the car door, she dives in the back seat and cowers on the floorboard behind the seat. I don't know what I can do to make her less afraid.