In court, the truck driver claimed he didn't remember the accident and that he had fallen asleep at the time of the crash.
The truck he was driving had flipped over on Route 40 outside of Borås one morning in early September.
During an initial interrogation, the man admitted that he was pleasuring himself when the accident occurred.
But during the trial, the German truck driver changed his story, alleging instead that he had succumbed to the need for sleep rather than sex when he flipped his rig.
According to the driver, he hadn't slept for several nights in a row, the local Borås Tidning (BT) newspaper reports.
When police arrived on the scene of the accident, the man was sitting in the driver's seat, naked from the waist down.
On Wednesday, the man was convicted of careless driving, assault, and sexual harassment by the Borås District Court.
The additional charges stem from the man's behaviour following the accident, when he hit a nurse and then started to masturbate while being interrogated by police.
An evaluation of the driver revealed that he may have suffered from a serious mental disturbance at the time of the accident.
The prosecutor argued that the man needed psychiatric care, and the man's defence attorney agreed.