She should pray outside standing even if she prays by the side of the road.

I had a discussion with a woman. I told her that there is no excuse for a person for not praying a prayer on time except oversleeping and forgetfulness(and may be other personal special fatwas, like a surgeon). She said I cannot as a women when driving home from work stop at a gas station and pray outside. I said you have to if you know that if you don’t stop before home, you will miss the time of prayer. The real issue here I think is that she is a women. Can a women pray outside where non-mahram can see her or should she pray inside her car or wait till she get’s home? Is there any excuse to miss the prayer time?