National Highway Traffic Safety Administration launched the investigation after receiving 124 reports from the consumers about the quality and safety of Toyota Pirus vehicles. Sudden unintended acceleration, that is  hitting a top speed of 97 mph of Toyota Pirus, is the reason that 2.3 million Toyota vehicles were recalled in early January.

The Toyota Prius is the ninth Toyota model to experience reported issues. This model was not a part of the January recall but was included in the October recall, as models manufactured between 2004 and 2009 were recalled for floor mat issues. That recall had nothing to do with brake failure.