Having been on the autobahn in a shitbox Renault econobox rental, 100mph is plenty fast. In North America (especially the rust belt) with how shitty the vehicle safety inspection standards are, I honestly don't trust the people around me to have maintained their car to an adequate standard to be safe driving at 100mph. Don't even get me started on how shitty people's driving skills tend to be.

A car is already a lethal projectile at 60mph. I don't like the idea of increasing the lethality potential for the average highway driving mistake.