To answer your original question.
By maintaining and securing ABCs. Taking spinal precautions loading the pt and transporting to a trauma center.
Large bore iV in route. Other treatments would be splinting, needle d, as needed.
In hospital, based on the MOI and injuries a level 2 or 1 trauma will be called with sub specialties called as needed.
The same is done if it’s a one car MVA or multi car. One difference would be if another pt in same car died, it will automatically be upgraded to a level 1 trauma. But that goes under the category of MOI.
Is there something specific your asking?