If someone doesn't wear a seatbelt and kills another person as a result who is wearing a seatbelt could that person face a manslaughter charge?
I can't get a good answer for this as Google is thinking I'm talking just solely on the driver. I'm including passengers who don't. I've seen PSAs that tell you the dangers you pose for others as well when you don't wear a seatbelt. So if you don't wear a seatbelt and that results in someone being killed could you not wearing a seatbelt mean you get a manslaughter charge?
Are you saying the driver is wearing the seatbelt, the passenger(s) aren't?
And how does the death result? Is it because of an accident? Are they messing/moving around in the car? Are they legally allowed to not be wearing a seatbelt in the vehicle?
There's too many undefined variables I think for anyone to give you a solid answer.
I've heard it mentioned that a passenger in the rear without a seat belt becomes a projectile in a crash and can kill or injure the person sitting in front of them.
That's on the driver. If you're driving, you are responsible for everyone in the car and out of it. If you drove off with someone unbuckled, that's on you.