"When the automobile industry in the United States was threatened by the popularity of cheaper more fuel efficient Japanese cars, a 1981 voluntary restraint agreement limited the Japanese to exporting 1.68 million cars to the U.S. annually as stipulated by U.S Government.
The Japanese automobile industry responded by establishing assembly plants or "transplants" in the United States to produce mass market vehicles. They also began exporting bigger, more expensive cars (soon under their newly-formed luxury brands like Acura, Lexus, and Infiniti)."
Now that's from Wikipedia and I understand you'll want better sources than that so, I'll have to get that off my pc at home. It was also corroborated to me by a retired Honda rep.