"A truck carrying about 30 people, planks of wood and coal overturned, apparently trying to avoid a motorcycle that had three passengers," said Jean-Henry Petit, the civil protection department's technical coordinator for the Nord department.
The truck was en route from Saint-Raphael, a town some 40 kilometers from Cap-Haitien, and had almost reached its destination when the accident occurred, Petit said.
"No one who was in the truck or on the bike was spared in the accident," Petit added.
One woman died midday from her injuries, while 16 others, including one of the passengers on the motorcycle, died at the scene.
The victims' bodies were being kept at a public hospital before being returned to their families.
The 18 injured were transferred to medical centers in Cap-Haitien. Of these, 13 people are in serious condition, Petit said.