This involves some of Toyota's most popular cars, including the RAV4 (2009-2010), Corolla (2009-2010), Matrix (2009-2010), Avalon (2005-2010), Camry (2007-2010), Highlander (2010), Tundra (2007-2010) and Sequoia (2008-2010).
Toyota says the pedal mechanism can wear down, causing the accelerator to become harder to press, or even get stuck.
This comes on the heels of Toyota's biggest recall ever for a floor mat problem that could lead to unintended acceleration.
"Early Show" consumer correspondent Susan Koeppen notes that, in September, Toyota recalled more than four million vehicles because floor mats were trapping the accelerators, causing sudden and unintended acceleration.
Experts say unintended acceleration can happen on any car, any day, any time. If it happens to you, would you know how to stop that runaway vehicle?
Koeppen reported on a shocking crash occurred on a highway near San Diego.
In a 911 call, the caller said, "Our accelerator is stuck."
The operator replied, "I'm sorry?"
The caller said, "Our accelerator is stuck."
Behind the wheel of a runaway Lexus was Mark Saylor -- an off-duty California Highway Patrol officer. His wife and daughter were passengers, along with his brother-in-law, who was on the phone with 911.
Saylor's brother-in-law said in the 911 call, "We're approaching the intersection. Hold on. Pray."
Moments later, the car hit an SUV, plowed into an embankment and burst into flames. Everyone in it killed.
Joe Audal, a cousin, told CBS News, "You couldn't believe something like that would happen to your loved ones."
Saylor's family was shocked when investigators blamed the accident on a poorly-fitted floor mat, which trapped the accelerator at full throttle.
Audal said, "To have a car stuck like that, it's a runaway machine that you have no control over."
According to the National Highway Traffic Safety Adminstration, over the past three years, there have been more than 100 incidents of unintended acceleration linked to Toyota vehicles like the one driven by Mark Saylor.
Consumer Reports car expert David Champion told CBS News, "This happens very rarely but, when it does happen, it can be a very scary event."
Champion says unintended acceleration can happen to anyone driving any car.
So what should you do if it happens to you? To find out, Koeppen and her team went to the Consumer Reports auto test track and wired a recently recalled car with cameras.
Champion said, "We're going to get up to 60 miles per hour."
To simulate unintended acceleration, Champion floored the gas pedal.
"The car is starting to accelerate," Champion said. "I'm putting my foot on the brakes and it's really, really having a hard time to really stop the car."
Koeppen asked, "You're pressing down as hard as you can?"
Champion replied, "As hard as I can and the car is still moving."
And pumping your brakes won't do much, either.
Champion explained that's because, "Each time you lift off, you're losing brake pressure, and I'm pressing down as hard as I can and this car is continuing to move."
He says what you should do is put the car in neutral.
"Put your foot on the brake, put the car into neutral and the car will stop," Champion said. "When you're stopped, just turn the engine off."
To prevent unintended acceleration, some cars, such as the Volkswagen Jetta, are now being built with "smart throttle" technology, which enables the brake to override the accelerator.
Champion said, "Full-throttle acceleration. Foot on the brake pedal."
The car stopped.
"Oh, wow," Koeppen said.
Champion added, "And that's with my foot still firmly on the accelerator."
Audal, Saylor's cousin, told Koeppen, "I know in my heart that Mark did everything to stop that car."
The Saylor family plans to sue Toyota and the Lexus dealer for the deaths of their loved ones, and they hope future tragedies can be prevented.
Audal said, "We're still in pain, and we just hope that something good comes out of this."
The Lexus dealership declined to comment. Toyota issued a statement, saying, "Our hearts go out to the friends and family of the Saylors. Unfortunately, we are unable to comment on matters of litigation."
On "The Early Show," Koeppen also answered a few questions about the Toyota recalls.
Question: We're talking about two different recalls. Let's talk about the floor mat recall first. What is Toyota doing about that problem?
Koeppen's Answer: Toyota is redesigning its accelerator pedal to reduce the risk of it getting trapped under the floor mat. The company has also told consumers to remove their floor mats and wait for replacement mats and Toyota is making the brake override system standard on most models by the end of the year.
Question: What about the fix for this latest accelerator pedal recall?
Koeppen's Answer: Toyota says the pedal problem does not cause unintended acceleration. The automaker is working on a solution. Toyota is telling drivers if you experience this pedal problem, pull over and call your dealer.
Question: In a runaway vehicle, why not just shut down the engine right away or pull up the emergency brake?
Koeppen's Answer: Champion says you don't want to do that. If you use your emergency brakes, the vehicle could flip. And, if you turn off the engine without shifting into neutral, you could lose power assisted steering, making it harder to turn the wheel.