Neuromuscular mix-up behind pedal confusion
Older drivers are more likely to experience pedal confusion and the unintended acceleration of their vehicles than younger motorists.
There have been thousands of cases of accidents occurring when drivers hit the gas but are convinced they are applying the brakes and researchers believe it is the result of a glitch in our sensory motor response.
“There’s always a degree of error in the actions we undertake,” said Luc Tremblay, associate professor and associate dean of research at the University of Toronto’s faculty of kinesiology. His area of expertise is multi-sensory integration.
“So in this particular case, if the receptors in your leg are interpreting your foot on the brake, you cannot think you’re actually on the gas pedal. You think the car is not responding to you pressing the brake and you end up pressing even harder on the gas because it feels like the limb is on the brake pedal.”
Tremblay said when we age, our senses, such as vision and hearing, diminish as do the receptors in our limbs, muscles and tendons.
He said when we reach for a cup of coffee and thrust our arm forward, we have the visual assistance to grasp it correctly, but in the case of using our leg on the gas and brake pedals we’re operating our limbs without visual assistance, so there’s more chance for error.
Tremblay also points out that because the left hemisphere of our brain controls the movement of the right side of our bodies, and viceversa, the 10 per cent of the population that is left handed, and therefore has left-foot dominance, would be better at driving with the use of their left legs.
“One of the great leaders in our field of sensory motor behaviour is Dr. Richard Schmidt,” Tremblay said.
A psychologist and ergonomist, Schmidt is hailed as the leading expert on pedal confusion and his research has indicated drivers who use their right foot for the accelerator and left to brake would be less likely to confuse one pedal for the other.
Professor emeritus of psychology at UCLA, Schmidt was one of the experts investigating the human factor in more than 150 serious and fatal accidents in the 1980s where cars, specifically the Audi 5000, suddenly sped up and crashed, which led to the German carmaker to install “smart pedals” on their vehicles, as did other manufactures.
Transport Canada determined that the Audi 5000’s unintended acceleration accidents were caused by driver error and the U.S. National Highway Traffic Safety Administration (NHTSA) found there was no electromechanical defect that could have caused an Audi to suddenly accelerate. In 2010, the NHTSA found that 35 of the 58 cases of Toyota vehicles that crashed were due to sticking gas pedals or motorists getting their feet trapped in floor mats, and not driver error, which resulted in the global recall of eight million of its vehicles.
Since then, Toyota and most other automakers have adopted smart pedals, but that hasn’t prevented pedal confusion, as it is still a factor in some collisions.
“Based on my experience in the 1980s helping investigate unintended acceleration in the Audi 5000, I suspect that smart pedals cannot solve the problem,” Schmidt wrote in an opinion piece, titled Braking Bad, for the New York Times, as the NHTSA was preparing its report to the U.S. Congress regarding the unintended acceleration of Toyota vehicles in 2010.
“In these situations, the driver does not really confuse the accelerator and the brake,” Schmidt wrote. “Rather, the limbs do not do exactly what the brain tells them to. Noisy neuromuscular processes intervene to make the action slightly different from the one intended.
“The driver intends to press the brake, but once in a while these neuromuscular processes cause the foot to deviate from the intended trajectory — just as a basketball player who makes 90 per cent of his free throws sometimes misses the hoop.”
Schmidt concluded: “This effect would be enhanced by the driver being slightly misaligned in the seat when he first gets in the car. And he added: “When the car accelerates unexpectedly, the driver often panics and just presses the brake harder and harder.”
Schmidt also pointed out that a General Motors study found that people 60 to 70 had six times the rate of unintended acceleration compared with 20- to 30-year-olds.