A medical emergency is being investigated as a possible cause for a single vehicle fatality in Nanaimo on Sunday.

Witnesses say a 73-year-old man was seen driving erratically just before the crash.

He struck a median and several signs going north on Highway 19A near Terminal Park Mall.

Then his vehicle turned onto Poplar Street and rolled down an embankment. The man was found deceased inside the vehicle.

Drugs, alcohol and speed have been ruled out as factors for the crash. Investigators are exploring the possibility that the driver may have experienced a medical emergency prior to the crash.

BC Coroners Service along with an RCMP Traffic Analyst attended the scene.

The family of the deceased has been notified and the investigation is continuing.