Safety regulators may require all new cars to have braking systems that force the engine to return to idle, part of a response to unintended acceleration problems reported in Toyota Motor Corp vehicles.

Transportation Secretary Ray LaHood also told a congressional hearing that it was imperative that Toyota put a high-ranking U.S. executive in charge of U.S. safety issues.

Senate Commerce Committee Chairman John Rockefeller opened the hearing saying Toyota let profits trump safety and U.S. regulators had failed to aggressively oversee the automaker in the years leading up to its recent big recalls.

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 the unintended acceleration in a range of models and braking problems with its Prius hybrid.

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, said Rockefeller, a Democrat from West Virginia.

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 associated with complaints of alleged unintended acceleration in Toyota vehicles, the U.S. Department of Transportation said.

The new head of the National Highway Traffic Safety Administration, David Strickland, defended agency investigations of Toyota, saying its response was absolutely appropriate.

Strickland also said Toyota's bigger fleet had boosted the number of complaints. They had the same percentage of sudden acceleration issues as other manufacturers. They just had more of them because they have more cars.

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.

Toyota has already said it will retrofit a brake override into a range of its vehicles as an additional measure, as well as incorporating the feature into new vehicles.

LaHood said transport officials were looking at whether that should be a mandatory feature for all automakers.

As a part of our investigation and review we are looking at the possibility of recommending the brake override system in all manufactured automobiles, he told the committee.

LaHood also said the law regulating how former regulators can be employed by the auto industry needs to be tightened up.

TOYOTA EXECUTIVES

Later on Tuesday, the Senate Commerce Committee was due to hear from three Toyota executives.

Toyota North America President Yoshi Inaba, in written testimony, 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, adding that Toyota dealers have so far fixed more than 1 million recalled vehicles.

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 U.S. 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.

Rockefeller reserved his sharpest criticism for NHTSA. NHTSA's actions and inactions in the years leading up to today are deeply troubling.

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.

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.

Agency supporters say lacks resources and expertise to conduct investigations of sophisticated engineering and software systems found in today's vehicles.

Toyota's chief engineer, Takeshi Uchiyamada, said in his written 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 rechecking its electronic throttles and has contracted with an independent consultant to look into them.

(Reporting by John Crawley; Additional reporting by Karey Wutkowski in Washington and Bernie Woodall in Detroit; Editing by Maureen Bavdek and Tim Dobbyn)

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