On the same day Toyota was trying to reassure the public of its safety, another driver claimed his Prius was accelerating out of control.

The beleaguered automaker called the press to its U.S. headquarters in Torrance, Calif. Toyota experts offered evidence that the acceleration problems with their cars were mechanical and not electronic.

"We have found no signs that electronics have anything to do with unintended accleration," explained Toyota's Mike Michaels.

Driver Can't Stop His Prius

However, just a short distance south, one Prius was said to be speeding out of control. After the driver called 9-1-1, a California Highway Patrol officer pulled up alongside.

"I could tell he was physically trying to break and the vehicle was barely slowing down. And then I noticed it would accelerate again and we were up to 90 miles per hour," CHP Officer Todd Neibert recalled.

"It got down to 55 and I pushed the button and shut it off and it didn't shut off," Prius owner/driver James Sikes claimed. "I did it a couple of times more. It did shut down, kind of rolled to a stop, till it bumped into the back of his car."

Sikes said he had been worried about his 2008 Prius. In fact, he took it to the dealer just two weeks ago.

"I gave them my recall notice and they handed it back and said I'm not on the recall list," he claimed.

Car Maker Has Recalled 6 Million Vehicles Since Last Fall 

Since last fall, Toyota has recalled more than 6 million U.S. vehicles with acceleration problems. Regulators have linked 52 deaths to crashes allegedly caused by the accelerator.

Toyota dealers have fixed more than 1 million vehicles. But the U.S. government has warned that if Toyota's remedy does not properly address the problem, it will order Toyota to develop another solution.

Congress is continuing to investigate Toyota. A house committee now wants to look at a 2006 employee memo that raised concerns about safety shortcuts.