The accident happened after the truck skidded and the trailer ended up over the road, where the car then ran into the trailer.
The driver was trapped and taken by ambulance helicopter to Falu hospital.
There she has now died from her injuries.
The truck driver is uninjured.
- There was lightning at the scene, so the probable cause of the accident could be the slip.
The car was hanging on the railing, says rescue leader Kalle Wallberg.
The police first opened a preliminary investigation into negligence in traffic and causing bodily harm.
The crime classification is now changed to causing the death of another.
Both vehicles were impounded for technical examination.