what is the correct way to transport a sefer torah in a car?
The correct way is to make sure that the sefer is transported in a way befitting it i.e. wrapped in a talis and someone holding it. If that is not possible wrap it also in another piece of material and place it on the back seat. (make sure it is secured that ח”ו it doesn’t fall.
Brochos 19 a, Y:D 282:3, Aruch Hashulchan 282:6