WASHINGTON - Complaints to U.S. regulators of unintended acceleration in Toyota Motor Corp. vehicles are down sharply as separate government and expert reviews of the matter move forward, Reuters reported.

National Highway Traffic Safety Administration documents made available to a National Academies of Science panel examining vehicle electronics as a possible cause of unwanted acceleration industrywide illustrate volatile complaint trends for Toyota and other automakers.

The quality of Toyota's cars -- once a benchmark for the industry -- has come under scrutiny since the world's top automaker recalled about 10.8 million vehicles globally since late last year, mostly for problems of unintended acceleration.

Reduced complaints for Toyota this summer, which regulators believe is partly due to ebbing publicity, do not alone substantiate the automaker's contention that its electronic systems are sound. But the drop could be an indicator that fixes for millions of recalled vehicles worldwide for mechanical and equipment problems linked to unwanted acceleration are working.

"We do feel our remedies have been effective," spokeswoman Cindy Knight said.

Regulators, who review each complaint, say complaints generally fall off when publicity eases even though Toyota has recalled thousands of other vehicles this year for other problems -- including braking on its signature Prius hybrid.

The unintended acceleration recalls in October 2009 and in January at the core of Toyota's safety crisis involved floor mats that could jam the accelerator pedal and pedals that did not spring back as designed.

Since 2000, electronic throttle control was cited in complaints associated with 52 Toyota crashes that reportedly killed 62 people, according to NHTSA's most recent figures. Regulators are reviewing complaints alleging 31 additional deaths unrelated to electronic throttle complaints.

Toyota is due to file an update soon with NHTSA on vehicles serviced under the big recalls, which regulators analyze to see if remedies are successful. The floor mat and "sticky pedal" recalls required design changes or replacement products.

Toyota has so far made repairs and other fixes on 1.7 million vehicles, or 78 percent of the recalled number, for "sticky pedals," and nearly 40 percent, or 2 million, of models recalled for loose floor mats, it said. Certain Tundra pickups and Avalon and Camry sedans had both problems.