The move appears to be a purely preemptive measure, or an added safety feature, as the Japanese automaker is not aware of any instances of unintended acceleration, a company spokesman in Japan told AN.
In such a system, any press of the brake pedal would override the throttle, so even if the throttle (or accelerator pedal) were to stick open, the driver could come to a safe stop and the engine would return to idle. There might also be an additional mechanical check to supplement electronic signals.
Toyota recently announced that it would install brake-override systems in all of its U.S. models by 2011. The 2010 Toyota Avalon and Camry models already have the devices, while the Sequoia, Venza, and Tacoma will soon get them.
In light of recent federal hearings regarding the Toyota accelerator-related issues, Transportation Secretary Ray LaHood is considering a recommendation that all U.S. new vehicles be equipped with these brake overrides, which cost about $50 per vehicle.
According to Automotive News, Nissan is the only Japanese automaker to use a brake override across (almost) its entire lineup, while Mercedes-Benz, Volkswagen, and Chrysler include the feature on many vehicles.