There's a point where speed becomes inherently unsafe due to visual limits. If cars were able to travel at Mach 2, then you'd be constantly at risk of getting i

There's a point where speed becomes inherently unsafe due to visual limits. If cars were able to travel at Mach 2, then you'd be constantly at risk of getting into a crash whenever you change lane, because cars can approach quicker than you can make a decision. There will be an upper speed limit somewhere, it might just be higher than cars can currently drive. Also unrestricted parts of the autobahn have a pretty bad safety record.