1) When you "stop" backing and looking forward and turning, did you put the gear in the forward position? You did not say in your post. Is it posible that you were still backing?
2) I am not an expert on cars. However, whenever I change from moving forward to moving backward, I have to stop the car first (push break), then move the gear. In other words, if your neighbor was moving forward as you thought, it would be quicker and more instinct reaction to continute move forward but turning away from your car. If your neighbor's reaction is backing onto his drive way, he probably was stopped when your car backed into his.
I might misread your post though.
2) I am not an expert on cars. However, whenever I change from moving forward to moving backward, I have to stop the car first (push break), then move the gear. In other words, if your neighbor was moving forward as you thought, it would be quicker and more instinct reaction to continute move forward but turning away from your car. If your neighbor's reaction is backing onto his drive way, he probably was stopped when your car backed into his.
I might misread your post though.