Toyota Motor Corp executives in North America will have more authority over recall decision-making under quality control changes that will also give safety a sharper focus in vehicle design, company officials said on Tuesday.

The automaker's North American president, Yoshimi Inaba, said in prepared testimony for a U.S. Senate Commerce Committee hearing, the overhaul will allow Toyota to better share quality and safety information across its global operations and with regulators.

An independent review panel headed by Rodney Slater, transportation secretary in the Clinton administration, would assess the changes to ensure they conform to best industry practices, Inaba said.

Inaba restated Toyota's apology for losing customer focus during its period of rapid global growth, a condition that fueled sharp U.S. criticism of its attention to safety and triggered recalls of more than 8 million cars and trucks worldwide for unintended acceleration and braking problems.

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

Unintended acceleration in Toyota and Lexus vehicles has been linked with at least five U.S. crash deaths since 2007. Authorities are investigating at least 29 other consumer complaints and other reports alleging fatalities over the past decade.

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.

The panel headed by John Rockefeller of West Virginia will focus on recalls in 2009 and 2010 with special emphasis on criticism that regulators at the National Highway Traffic Safety Administration were not aggressive enough when investigating complaints over the years of unintended acceleration in Toyota vehicles.

Transportation Secretary Ray LaHood, who will also testify, has spearheaded a tougher government response toward Toyota in recent months -- triggered by a Lexus crash in San Diego last August that killed four people.

Until 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 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 become jammed in the accelerator and sticky gas 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.

Toyota's chief engineer, Takeshi Uchiyamada, said in his Senate testimony that Toyota has extensively tested its software-driven electronic throttles and has found no problems. NHTSA has also never uncovered any problems, but is again reviewing the matter. Toyota is also rechecking those systems and has contracted with an independent consultant to look at them as well.

Members of Congress at two hearings in the House of Representatives last week suggested legislation would be needed to strengthen NHTSA, an agency supporters say lacks resources and expertise to conduct investigations of sophisticated engineering and software systems found into today's vehicles.

Lawmakers in the Senate are expected to recommend the same step, but underscore the need for urgent action.

Shinichi Sasaki, the executive who heads Toyota quality control, said in separate testimony 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.

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.

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

(Editing by Maureen Bavdek)