I've driven across germany recently, and having driver in US well over 90,000 comparison is rather interesting.
No speed limit in germany, but roads feel much safer. you always know what to expect of people. Passing on the right is forbidden ( you lose your licence on the spot if I'm not mistaken ) and people generaly keep to the right unless passing ( this goes for cars doing 150 mph as well !!! )
In US people pass whereever they feel like, drive slow in left lane and there is a speed limit ( none in parts of germany ).
Aparently death rate per 100,000 travelers is something like 2x higher in US then it is in germany, so maybe speed itself is not a problem ?