APIA, Samoa -- Sometime in the early morning hours of Sept. 7, residents of this small Pacific island nation will stop their cars, take a deep breath, and do something most people would think is suicidal: Start driving on the other side of the road.

Samoa is about to become what's believed to be the first nation since the 1970s to order its drivers to switch from one side of the road to the other. That's spawned an islandwide case of road rage. Opponents have organized two of the biggest protests in Samoan history, and a new...