Some basic things you need to do:
1)Jessica needs to have a target path track. Don't worry about the car. She knows how to drive it.
2) Send Jessica an input telling her to enter the vehicle with a parameter of 0 for the driver seat I believe.
3) The car needs an input that says when the player is on, meaning the player is in the car, Jessica start driving.
4) You as the player use the passenger side door and get in. Jessica should start forward.