Wheel Falls Off

Driving on I-71 South between Columbus and Cincinnati, all of a sudden the tire comes off of the car in front of me, no one was hurt, but it's not something you see every day. I stopped to help the driver, she had a phone so there was not much more I could do. I looked at the front right wheel well where the tire used to be, the tire and rim were missing, but the lug bolts where in fine condition, it appeared to me as though someone had removed the lug nuts.