I can tell you firsthand that seatbelts prevent injury. I was recently in a wreck where the driver overcooked a turn in the wet on the off-ramp from the Mass Pi

I can tell you firsthand that seatbelts prevent injury. I was recently in a wreck where the driver overcooked a turn in the wet on the off-ramp from the Mass Pike to 128 We hit the guard rail on the inside of the turn once or twice, and the concrete barrier on the outside of the turn twice, including head-on at the end of our spin-out. Either the driver or I or some object hurled forward between the seats folded my phone in half, which was sitting in a narrow pocket in the center console. I sprained a finger on the door handle. I would surely have hit my head more than once on the windshield and side glass had I not been belted in. Once out of the car we could tell it was quite a wreck: the engine was pushed in and the whole front end crumpled. The front wheels were destroyed. Both sides of the back were rounded off. The doors opened with some difficulty. The smell of airbag propellant makes me think it must be similar to model rocket propellant.