Amid its widening recall crisis, Toyota Motor Corp. said it had moved closer to adopting changes to its push-button ignition system to give drivers an added margin of safety if their vehicles accelerate out of control.
Executives at the company's headquarters in Japan are considering redesigning the keyless ignition system, known as Smart Key, to allow drivers to shut off the engine by tapping the button three times in a row, company spokesman Brian Lyons said.
Currently, Toyota and Lexus vehicles with a push-button starter can be shut off when in motion only by depressing and holding the button for 3 full seconds, a procedure that safety experts have suggested is counterintuitive and can prolong runaway acceleration incidents. A redesigned system would allow either method to kill the engine.
"The thought is, what would somebody be doing in a situation where they absolutely had to shut down the vehicle?" Lyons said. He said the changes would be implemented only on future-year production cars rather than vehicles already on the road or being built now.
"It would not be part of a recall situation," Lyons said.
The Smart Key system was highlighted by investigators for the National Highway Traffic Safety Administration as a "significant factor" in a crash involving a Lexus ES near San Diego in August that took the lives of a California Highway Patrol officer and three members of his family.
In the wake of that accident, Toyota announced the first in a series of major recalls aimed at addressing growing complaints of sudden acceleration in its vehicles. Toyota has recalled more than 10 million vehicles because of defects that can cause runaway acceleration or braking problems, with about 2 million vehicles involved in more than one of the actions.
Keyless ignition systems are only one potential factor in sudden acceleration, but their widespread adoption worries some safety experts.
Last month, The Times reported that 155 vehicle models in the U.S. offer keyless ignition systems, compared with 41 five years ago, yet there are essentially no federal or industry standards regulating the technology.
As part of that report, The Times noted that Toyota was considering changing the operation of the push-button system. News that those discussions had advanced to a specific potential remedy was first reported Wednesday by Consumer Reports.
Paul Green, a human factors expert at the University of Michigan Transportation Research Institute, said Toyota and other carmakers have designed push-button start systems with very little research about how consumers naturally expect such systems to operate.
Green said that if Toyota now rushes a redesign into production without any new research, "it is really risky."
Transportation Secretary Ray LaHood said last week that concerns about stopping cars with push-button starters were among the electronic-related complaints regulators were examining regarding Toyota.
Green said engineers have built in delays to engine shutdown out of concern that a child might push a power button and turn off the engine. Another concern of automakers is that the driver might inadvertently shut down the engine if power buttons can be activated by a single momentary touch.
But those concerns force the industry to balance the risk of two rare events, Green said -- a driver who has to shut down an engine deliberately in an emergency versus an unintended shutdown of the engine. Without research, it is difficult to know how to deal with those competing issues, he said.
Nearly every automaker that uses keyless ignition systems has implemented a slightly different procedure for emergency shutdown, with some requiring as little as a single tap and others requiring a lengthy hold-down. A vehicle traveling at 100 miles per hour covers roughly 500 feet -- nearly two football fields -- in 3 seconds.
Furthermore, many drivers of vehicles with push-button ignition are unaware of how to operate the system. The owner's manual for a 2007 Lexus IS, for example, warns motorists on Page 99: "Do not touch the engine switch while driving."
Toyota's manual for its 2009 Camry, by comparison, indicates on Page 129 that the engine can be shut down in an emergency by pushing and holding the button for more than 3 seconds.
According to Richard Pak, a professor of psychology at Clemson University who studies human interaction with technology, the safest kind of ignition switch is one that works in an intuitive manner. That's because in a panic situation, humans "revert to learned behavior."
"When you're out of control at 80 miles per hour, you're not going to remember complicated things," Pak said.
Toyota is also planning to install software that automatically brings the engine back to idle when the driver steps on the brake. Such a system, known as a brake override, is used by a number of other manufacturers.
Lyons said that Toyota would install a brake override on all new cars starting with the 2011 model year. In addition, the automaker is adding that program to four models involved in its 5.4-million-vehicle floor-mat recall -- Camry, Avalon, Lexus IS and Lexus ES. He said a decision had not been made about putting a brake override in the eight other models in that recall -- the Highlander, Corolla, Venza, Matrix, Prius, Tacoma, Tundra and Pontiac Vibe, which Toyota made in a joint venture with General Motors.
John Gomez, a San Diego attorney representing the family of the CHP officer killed last summer, said he was gratified to hear that Toyota would expand the keyless ignition system's functions but believed the brake override was more crucial.
"They should retrofit every vehicle on the road," Gomez said. "There is no defensible reason that the throttle should remain wide open when the driver has both feet on the brake pedal."
Times staff writer Jim Puzzanghera contributed to this report.