Windshields are made with safety glass and generally don't permit objects to pass through them (it can happen but it takes a tremendous force to break through the 2 panes of glass).
I was driving outside of Austin when something was made airborne by the pickup truck in front of me (something wood or metal, about this size and shape of an adult forearm - long and "clunky"). I was driving 60-70MPH and this item cracked my windshield and made a hole about 2 inches in diameter. I'm glad that it didn't go all the way through the window (it bounce off) and I'm glad that it did go "up (as my top was down on my convertible).
To wedge a person through the windshield deep enough that he doesn't fall out and deep enough that his body can rest on the hood... it seems to me that she must have been flying down the road.
Flying low... My son was going down a country road a few years ago and hit a foggy patch and didn't see the horse in the road. The horses head came through the windshild the body flew up on the roof and when it came down it landed on the road. He was probably going about 50 MPH on that particular road. We were thankful he had just dropped off his date or she would have been sitting in the passenger seat and would have been killed. From the pictures I have seen on TV it was probably the freeway.. I still can't imagine her driving home with a man on her hood and no one saw her unless it was VERY late at night and no one was on the roads and she didn't have far to drive.