Some Toyota and Lexus owners have suddenly found their vehicles in runaway acceleration to near-maximum speeds, and there've been a number of fatalities and serious injuries. See last night's ABC News report, and be sure to run the video report: http://abcnews.go.com/Blotter/RunawayToyotas/sudden-acceleration-toyota-cars-owners-rebel-accidents/story?id=8980479. See also http://www.theautoindustrieblog.com/2009/10/lexus-lacks-critical-safety-feature-for.html
As noted, Toyota has tried to blame it on driver error and incorrectly-sized floor mats catching and holding down the gas pedal; it has initiated a recall of 3.8 million drivers' floor mats. Some owners are now angry at Toyota, saying that's not it, but something else such as its engine-management computer. Toyota is (very!) reluctantly looking at that, too. I know Lexus can get stuck in arrogance and denial over the supposed perfection of its cars.
A possible runaway acceleration problem has plagued some cars in the past, such as Audi. Interestingly, makers' philosophies seem to vary by country! This NYT article and comments only a month ago summarizes the "Smart Gas Pedal" solution: http://wheels.blogs.nytimes.com/2009/10/07/smart-gas-pedals-may-solve-floor-mat-problem/ With this system, applying brakes and gas at the same time DEACTIVATES THE GAS PEDAL. This system has been installed on mostly German cars -- Audi and VW since 2001 and BMW since 2005. Mercedes also has it.
In contrast, Japanese cars DO NOT use this system, except Nissan will put it on Infinitis in 2010. The U.S. as usual is also way behind the curve, except Chrysler (because owned by Daimler?). The system really works: http://blogs.consumerreports.org/cars/2009/10/toyota-recall-putting-stuck-floor-mat-survival-strategies-to-the-test.html.
Now, what do YOU do if you get caught in this situation? I'll bet, with a madly racing engine, a sense of panic, and an inability to slow the car much with the brakes, you'd try turning off the engine. That'd be my response, too! Unfortunately, that will kill the power brakes and power steering, and if you turn the key too far, it would lock the steering!
The proper way would be to put it in neutral, even though the engine will really rev, and bring the car to a stop BEFORE shutting off the engine. http://blogs.consumerreports.org/cars/2009/10/putting-a-car-in-neutral-might-save-your-life.html. Unless, of course, you have a car with a smart throttle.
I'm still not sure I'd do it right....