system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are indefinitely high speeds allowed on the Autobahn? How can the freeway design account for such high speeds (in terms of safety)?
gpt
German driving tests are hard and the minimum age is 18. 
Strickt car checkups every 2 years.
Good condition of the roads.

So you have better drivers, cars and roads. 
Don't be fooled though, not everywhere you can drive as fast as you want. Crowded parts of autobahn near the urban are usually limited. 
The recommended speed is 130 KM/h on the places where there is no limit.