The young Ralph Nader testifying before Congress a half-century ago. He is now weighing in on R&D spending claims by Toyota.

The man who helped launched the auto safety movement by challenging General Motors is now taking on the company that has taken over as the world’s largest automaker.

Ralph Nader is challenging Toyota to explain claims it is spending $1 million an hour on R&D, a figure it is using in an ad campaign aimed at overcoming concerns about a year-long safety scandal.  By Nader’s calculations that works out to a whopping $8.7 billion annually.

The ad campaign, which was first launched in June, appears to link that spending specifically to the problems facing Toyota, proclaiming, “At Toyota, we care about your safety. That’s why we’re investing one million dollars every hour to improve our technology and your safety.”

“That is an astonishing amount, compared to your industry peers, to be spent on safety R&D,” Nader says, in a letter sent to Jim Lentz, head of Toyota’s U.S. sales subsidiary.

A failed candidate for president and perhaps the nation’s best-known automotive safety advocate, Nader’s missive directly asks Lentz for clarification on the spending.

Lentz, through a spokesperson, said he will respond directly to Nader, but the consumer gadfly isn’t the only one asking.  The New York Times has also raised the question and gotten a more amorphous response, Toyota explaining, “The $1,000,000 an hour claim represents all Toyota R&D spending globally, much of that allocated to new quality and safety technologies.”

That is still a huge figure, of course, and what is unclear is how Toyota is separating research and development spending from the more general investment it – like the rest of the industry – pumps into each product development program.  If those efforts are included then the number is not anywhere near as spectacular as the advertising campaign might make it seem.

During an appearance at the Automotive Press Association, last week, Toyota’s second-in-command, Don Esmond, suggested that the maker is beginning to overcome the image problems that were touched off by an October 2009 recall for sudden acceleration.  Over the last year, the Japanese automaker has recalled about 9 million vehicles in the U.S. alone for a variety of safety-related issues.

Nader first made his name with the book, “Unsafe At Any Speed,” which focused on problems with the Chevrolet Corvair.  GM took aim at the critic by hiring private investigators to follow Nader, provoking an even bigger firestorm of criticism and ultimately driving the maker’s first rear-drive/rear-engine model off the market while turning Nader into a national figure.