A general speed limit would actually help a lot, even a relatively strict one of 120 km/h. But it will not protect us from these braindead idiots - they simply ignore such limits.
Like the singer of the "Böhse Onkelz" did 11 years ago just a few km further down the highway in a section with a speed limit of 120 km/h - he crashed into a slower car with more than 200. Just a bit more that two years in prison for killing someone.
That highway actually has only a few and relatively short unlimited sections, and the race i showed started in a section with speed limit.