Searches already done :
Googled as many permutations as I can think of involving 1950’s/car/auto/vehicle/accident/wreck/i
Background : My Main Character is driving a twisting-turning stretch of highway and loses control of his car. He swerves to avoid an oncoming vehicle and the car crashes off the road into a ravine or similar. He’s thrown clear in the process, but his passenger (also male, similar height/age/build) is not, and upon impact the car catches fire/explodes. By the time anyone gets there to help, the car is destroyed, to the extent that there’s not much of the passenger left for ID. The other driver can ID the MC as being behind the wheel at the time the car went off the road, but didn’t see the passenger. The MC leaves the scene after the incident, so even if the police searched the area there wouldn’t be any trace of a second person involved.
ETA: I'm working on the idea that the impact and lack of seatbelts would have moved things around enough that any remains = the driver. Also, while I haven't completely settled on what the car is yet, chances are it'll be something like a Thunderbird, i.e. there'll be very little interior space to speak of.
Questions : There’s no immediate reason to suspect foul play, and there are plenty of witnesses from earlier in the day to comment on the erratic and on-edge behaviour of the MC. How much of an investigation would have gone into verifying the body in the car was actually that of the MC? Would they have been more likely to conclude from the witness/circumstantial evidence that my MC would be the only body in the wreck, or would post-mortem investigations have been standard in any case?
The story doesn’t involve the investigation itself; what I need to know is, given the time period and the investigative procedures involved then, how likely it would be that those involved would accept the MC (and not the mystery passenger) had been killed in the accident? If they were required to investigate further, how much time would pass before they realised the error and figured out the MC was still alive somewhere?
Thanks in advance for any help!