qiyaam

Performing Salaah in a car

Q: My wife and I do a lot of travelling by car. A lot of times the distances we drive are over 90km. Due to this, sometimes we have to pray on the side of the road or in a parking lot. If my wife prays outside the car like me, there are many people (men and women) who walk and drive by and could see her. In this case, is it permissible for my wife to pray sitting down in the car?