I went to an accident years ago (newspaper reporter) where two guys lost control and went off the right shoulder. Their vehicle started up a steep embankment and they were both thrown through the driver’s window and out onto the highway. They were immediately run over by a vehicle behind them.
When I arrived one guy was lying in the middle of the road covered by a sheet. Then I noticed a long red streak going down the road and ending at the vehicle that hit the the two. Yep, the second guy waas wedged under the vehicle and had been dragged down the road.
Somehow, the dead guys’ vehicle was barely damaged. The trooper told me they could have driven it away if they had been wearing seatbelts.
I always wear one and make others in my vehicle wear one.