That’s a good point, I didn’t think of that. Between that and the fact that you’d most likely be noticed idling at a light for hours, it makes no sense. The likely reasoning here to me is that she was with him that night, they had consensual sex, she stayed the night, and then went home in the morning. The attorney is trying to cover up the fact that the rape happened at X time but she didn’t return home until hours later and had to fill in that time difference while also giving a reason for why she didn’t go to the police (too exhausted).
Consider how easily it could happen to you - you have a person you’re dating sleep over, they go home the next morning, but later claim they were assaulted that night and they left right away but then fell asleep on the way home so that’s why they didn’t get home until the next morning.
I think something like that happened in Gone Girl now that I think about it. She had crazy sex with a guy and got roughed up, then went to the cops and claimed abuse.