Answer to Question 1
California was dealing with a unique air quality problem in the famous Los
Angeles smog. It was a public health problem of great magnitude and required a strong
response. The converters reduced greatly the cars' emissions.
Answer to Question 2
There are several reasons, the foremost of which is that few people travel by ship.
A different reason is that ships are relatively efficient at moving freight already, so the
payoff in savings is not so great as for other, less efficient, modes of transportation.