BURNS HARBOR — A Merrillville man died of natural causes Wednesday before driving his semi-trailer truck off the road.

Porter County Coroner Chuck Harris said Dragi Petrov, 56, was traveling westbound on U.S. 20 near Salt Creek Road when he apparently had a medical issue. The truck crossed both lanes of traffic before coming to rest on the south side of the road.

Minimal damage was done to the semi-trailer.

Petrov was transported to a local hospital and pronounced dead in the emergency room.

An autopsy Thursday showed Petrov died from natural causes and not as a result of the accident.

Another vehicle did suffer damage attempting to avoid the semi-trailer.