The mayor of the city of Jeremie, Ronald Etienne, told Reuters that the cause of the accident was not known.
The accident occurred near the coastal town of Roseau, east of Jeremie, according to media reports. Most of the dead were from the town of d'Anse d'Hainault on the far western tip of the southern peninsula, the reports said.
Haiti's rural road infrastructure is in poor shape though foreign assistance after the 2010 earthquake has led to improvements on the national two-lane highway in the southwest. REUTERS