She should be suing the lamppost manufacturer for making one in which a car would bounce off it when hit. The lawyers could argue that when struck, little "Magic Fingers©" should pop out and hold the car snugly against it to prevent it from careening off. Of course, she could also then sue for whiplash, but that's another story.
Why not just sue auto manufacturers for putting reverse into cars in the first place, knowing that people usually don't look behind when they're using it?
Better yet, she should sue them for putting mirrors in the cars, because the design of the car induces her not to use the more safe method of looking behind her?
Wait, wait, I got a better one! Sue auto makers for putting a GAS PEDAL in the car! If they had made a car that didn't move, none of this would have happened! Yeah! That's the (meal) ticket!
We oughta be personal injury lawyers. We could sue Burger King, the makers of the lamppost and the auto maker - not to mention the entire city of Detroit for letting the auto industry make it's home there. What do you say?