The way you sit in a car make it more feasible for different size people to use the seat belt.
In a school bus seat,all kids would have to have bolster seat for the correct fit.
The seat belt law was mostly lobbied by insurance companies.
The average life insurance pay out for death 250000,Top with another 40000 for accidental death.
Then cost of repair and lawyer fee's and the list goes on. The cost of a injury victim.00000, we the tax payers pay it.