The Autobahn 8 was closed after an accident near Leonberg (Böblingen district).
A man came off the road early Wednesday morning with his truck and hit the guardrail, a police spokesman said.
The truck driver was slightly injured.
How the accident came about remained unclear.
Leonberg - The police blocked the A8 in the direction of Stuttgart.
In addition, two lanes in the direction of Karlsruhe were initially closed.
The police later released a blocked lane.
There was a traffic jam about eight kilometers long in the direction of Stuttgart.
dpa