It's futile to actually have road-legal cars that go this fast because you can't do very much useful with the speed. This is much too fast for the human operator (driver) to safely react to things outside the cockpit, which is why for example Britain owns trains capable of 140mph in service but deliberately limits them to 125mph. Tests suggested drivers couldn't be relied on to reliably observe and react to a linesid…
What's stopping the trains from operating autonomously?