How did this tire fall off? Did the lugs snap after being hit? Did you feel any kind of vibration from the wheel before the accident?
Not sure of your description of the accident....going 65 miles an hour, and you try to steer away from the accident, you are bound to lose control...did the car cut you off by turning in front of you, or did it go through stop sign/light on a highway from the side?
was the accident investigated by the police?