WASHINGTON - Toyota Motor Corp let profits trump decision-making on safety and U.S. regulators failed to aggressively oversee the automaker in the years leading up to recent big recalls, a leading U.S. senator said on Tuesday.

We are all here today because we know that something has gone terribly wrong - the system meant to safeguard against faulty vehicles has failed and it needs to be fixed immediately, Commerce Committee Chairman John Rockefeller said at the panel's first hearing on Toyota's safety crisis.

Rockefeller said he would work on legislation to address safety oversight of the entire industry, not just Toyota, which has recalled more than 8.5 million vehicles worldwide in recent months for unintended acceleration and braking problems.

Unintended acceleration in Toyota and Lexus vehicles has been linked with at least five U.S. crash deaths since 2007.

Authorities are investigating 47 other crash deaths over the past decade linked to complaints of alleged unintended acceleration in Toyota vehicles, the U.S. Department of Transportation said.

In prepared testimony, Toyota North American President Yoshi Inaba reiterated Toyota's apology for losing customer focus during its period of rapid global growth.

We sincerely regret that our shortcomings have resulted in the issues associated with our recent recalls, Inaba said.

He and other Toyota executives detailed quality control changes to address concerns raised by lawmakers at the Senate hearing and at two similar hearings last week in the House of Representatives.

Executives in North America will have more authority over recall decision-making and safety will be given a sharper focus in vehicle design.

An independent review panel headed by Rodney Slater, transportation secretary during the Clinton administration, would assess Toyota's changes, Inaba said.

TROUBLING INACTION

Rockefeller said it was clear that somewhere along the way public safety took a back seat and corporate profits drove the company's decisions at Toyota. But he reserved his sharpest criticism for regulators at the National Highway Traffic Safety Administration (NHTSA).

NHTSA's actions and inactions in the years leading up to today are deeply troubling, said Rockefeller, a Democrat from West Virginia.

Until Toyota's first big recall in October, NHTSA had taken only modest action to address rising consumer complaints of unintended acceleration in Toyota and Lexus vehicles.

Lawmakers, safety advocates and consumers have also questioned whether regulators paid enough attention to the possibility that electronic throttle glitches were behind at least some of the automaker's problems with unintended acceleration after 2002.

Two major recalls over the past five months have focused on mechanical explanations for acceleration problems, including loose floor mats that can jam the accelerator and sticky accelerator pedals that do not spring back as designed.

Safety advocates say NHTSA, which receives more than 30,000 complaints annually, has historically been overly reliant on manufacturers and, in some cases, deferential to them.

U.S. Senate investigators have reviewed thousands of documents from the company, regulators and insurers over the recall firestorm that has jolted the company's reputation for quality and reliability.

Toyota's chief engineer, Takeshi Uchiyamada, said in his Senate testimony that Toyota has extensively tested its electronic throttles and has found no problems.

NHTSA has also never uncovered any problems with the devices but is again reviewing the matter.

Toyota is also rechecking its electronic throttles and has contracted with an independent consultant to look into them.

Members of Congress have suggested legislation will be needed to strengthen NHTSA, an agency supporters say lacks resources and expertise to conduct investigations of sophisticated engineering and software systems found in today's vehicles.

Shinichi Sasaki, the executive who heads Toyota quality control, said in separate testimony that the carmaker's quality assurance overhaul will cover vehicle design, manufacturing sales and service.

The automaker will emphasize safety in its designs with more focus on driver behavior and real world driving conditions, he said.

It will improve its network for collecting consumer information, establish new technical offices in the United States, and will review vehicle data recorders and enhance other diagnostic tools.

Inaba said Toyota dealers have so far fixed more than 1 million recalled vehicles.

(Reporting by John Crawley; Editing by Maureen Bavdek and Tim Dobbyn)

U.S. Toyota Safety