[toomanybeersies]

Although decapitation by windshield is unlikely (due to their design), you don't have to be going very fast to seriously damage yourself on the windshield if you're not wearing a seat belt.

I crashed a truck once, going maybe 30-40 km/h, wearing a seat belt. I ended up with some minor bruising from the seat belt, and no other damage, but everything else in the car went flying, including the glasses off my head. If I wasn't belted up, my head would've hit the windshield or steering wheel quite hard, and I likely would've needed to go to the hospital.