KAMAKURA, Kanagawa Pref. — Japan's most famous consumer activist is watching the safety problems enveloping Toyota with a sense of frustration.

For decades, Fumio Matsuda took on the country's powerful carmakers, bringing his engineering expertise to landmark court battles that won damages for consumers and led companies to make their vehicles safer.

Yet his success has yet to inspire a new generation of Japanese consumer advocates, and few have been willing to stand up to Toyota Motor Corp. in courts of law or public opinion.