Are recumbents more fatal in an accident than a regular bicycle?
I have been riding a recumbent for the last couple months.  Its a highracer so higher than a lowracer, and puts me at about even face height with sedan drivers.  Thats roughly even with the saddle on my road bike.  I have a flag but its not much above my head.


You're harder to see because you're behind cars rather than peaking over cars
As a rider you have more limited visibility of other cars for the same reason
BUT as something highly unusual on the road, drivers seem to perceive you better - the visual image passes from the lizard brain to the conscious brain and other road users notice you more.   I experienced the same thing when riding a tandem either solo or together, or when towing the kiddy trailer - vehicles gave significantly more passing room than they do when I'm on my boring upright road bike.




To address the "more fatal" part - an upright rider is higher than a sedan, so an accident is more likely to hit the bike and "scoop" the rider up and over a bonnet/hood/windshield.  With a lower bike, an impact will be more of a "push" leading to more impact and sliding, than a "lift" which would be more throw and impact with the ground or other objects.  

Personally, I'd prefer to ride defensively and avoid the potential accident all together, regardless which bike I am on.