Police from the major crash investigation section are trying to determine the cause of the collision. Police from the major crash investigation section are trying to determine the cause of the collision. Major crash officers are trying to determine what caused the collision on North West Coastal Highway at Hamelin Pool, about 20km south of Overlander Roadhouse, about 11.30am on Monday. Camera Icon Two people have died after two vehicles collide on North West Coastal Highway near Shark Bay Credit: Josh Osgood / SuppliedBoth patients are in a stable condition. The collision forced the closure of North West Coastal Highway for several hours.