Having touched/exceeded 50mph on all 4 of the recumbents I own/have owned, I can attest to the fact that 50mph is damn fast!
On a normal circular 20 mile route I use I comfortably exceed 35mph in several places and on another 40mph is easily passed every time. All of these descents have decent eye lines, no junctions for morons in tin boxes to emerge from and decent surfaces.
From my days riding upright bikes those top speeds would be a chunk slower, such is the benefit of the laid-back position.
I would encourage everybody to take it easy on strange roads and reduce the risks you are taking rather than increase the speed of any potential crash.