In many cars, a driver with a long torso and shorter legs can find that even when there is enough headroom to sit up straight, if they pivot forward from the waist their head quickly hits to visor or other part of the passenger compartment roof or frame. Does anyone know how to evaluate if this is safe? Videos of crash tests show the crash dummies (with headroom) do seem to move forward quite a lot during a crash.
The closer your head is to a surface the easier it will be to achieve contact between the two. So if you don’t fit in your car, you are obviously less safe.
I’m not sure what cars come with and without seatbelt pretensioners these days, but if this is a concern for you, I’d look for a car with them.