The only times that seatbelts and airbags really help is when hit directly on or semi-directly on. If you get T-Boned or rear ended then they are useless. If I get T-boned a seatbelt can actually make things worse. If I get rear ended then I am going to be pushed into my seat first and in that instant my arms and legs are going to be locking up and as such I definitely won't be going through the window. I can generally control what hits me in the front, I can't as easily control what hits me from the sides or rear.