Few automotive engineers believe in so-called "sudden acceleration". But until recently, there's been no way to determine what a driver what doing when he (or she) swears that he was pressing the brake pedal with all his strength even as the car accelerated.
Now, that's changed. Federal investigators say the latest highly publicized incident--in which a 2005 Toyota Prius in the New York City suburb of Harrison, NY, accelerated across a street and into a stone wall on March 9--appears to be the fault of the driver.
Dashboard - 2005 Toyota Prius 5dr HB (Natl)
Angular Front Exterior View - 2005 Toyota Prius 5dr HB (Natl)
Consumers must be informed about black boxes
2005 Toyota Prius
Black box: No brakes, full throttle
The Event Data Recorder, or "black box," in the Prius records at least several seconds of data from the car's electronic control systems. It was inspected by a team of six Toyota engineers and two officials from the National Highway Traffic Safety Administration (NHTSA).
The NHTSA said in a statement issued yesterday that the onboard computer systems in the Prius "indicated there was no application of the brakes, and the throttle was fully open."
In other words, the driver thought she was braking, but she wasn't--she was accelerating, with the pedal to the floor.
How can this happen? Richard Schmidt, a psychology professor at the University of California, Los Angeles, writes, "The trouble, unbelievable as it may seem, is that [it] is very often caused by drivers who press the gas pedal when they intend to press the brake."
He attributes this behavior to "noisy neuromuscular processes," when a limb doesn't quite do what the brain is telling it to do. So a driver's foot may deviate slightly from its intended path.
Older drivers, too?
Drivers who panic when a car accelerates when they expected it to brake immediately press even harder on the "brake" pedal--leading to further acceleration. Seemingly, this could explain what happened to the 56-year-old housekeeper who was driving the Prius.
Age may play a factor in the behavior as well, with the bulk of Toyota sudden acceleration complaints involving drivers aged 60 to 80.
Toyota fights back
Toyota publicized the NHTSA statement on its Harrison investigation, as it did the results of an earlier investigation into a San Diego incident. There, 61-year-old James Sikes claimed his 2008 Toyota Prius had sped out of control on a freeway for more than 20 minutes.
Toyota [NYSE:TM] issued a press release on Monday that pointed to "strong indications that the driver's account of the event is inconsistent with the findings of the preliminary analysis."
Black boxes to the rescue?
It may be black-box data, in fact, that exonerates carmakers from at least some of the blame for cases of so-called sudden acceleration. Back in the days of the notorious 1986 Audi sudden acceleration case, no data was recorded.
Shaken drivers often got a sympathetic treatment in the media, which tended to paint car manufacturers as selling hazardous products that jeopardized passengers' lives.
Black boxes standard in 2013
The NHTSA has finalized its rules governing Event Data Recorders, and they will be fitted to 2013-model-year vehicles, starting in September 2012. At that time, there will also be a requirement that owners can access their black boxes in some way.
In the end, the data may be what brings light into the confusion and darkness of these strange incidents. Stay tuned for much more to come on this topic.