Innate behavior determines how we steer a vehicle

Chuck Bednar for – Your Universe Online

Researchers from the Chalmers University of Technology have for the first time explained why people demonstrate a jerkiness while steering a motor vehicle, and their findings could result in improved safety systems that could correct dangerous movements before they even happen.

Ola Benderius, a Ph. D. student who has been developing models of driver steering behavior, and his colleagues explained that their research could make it possible to predict what drivers will do right as they start to turn the wheel. As a result, applications such as smarter anti-skid technology or systems to help fatigued drivers could be developed to make automobiles safer.

“Imagine a fatigued driver on the verge of running off the road,” explained Benderius, whose research has been published in the journal Proceedings of the Human Factors and Ergonomics Society of America. “He or she suddenly wakes up and reflexively initiates a very large corrective maneuver, a potential misjudgment that can lead to something very dangerous.”

“Since we are now able to predict how far the driver is going to turn the wheel, the vehicle’s support systems can identify potential misjudgments and intervene, which means a serious accident, such as the car travelling into approaching traffic, can be avoided,” he added.

The research helps solve a mystery that dates back to 1947, when British researcher Arnold Tustin developed the first model for how a person steers towards a target. Tustin identified a continuous and linear-control behavior known as tracking within control theory.

Tracking within control theory states that when a vehicle is driven, it corresponds to the driver gently and continuously following the road with the steering wheel. It has been the predominant theory for driving a motor vehicle ever since. However, when comparing the linear model with actual data, some deviations become apparent – most notably, jerkiness in the steering signal.

While giving a lecture on the behavioral theory of reaching, Benderius and co-author Gustav Markkula came up with the idea for their new study. They explain that when people move their hands from one point to another to pick something up, there is a direct relationship between speed and distance. The further away the object is, the faster we reach for it.

In this phenomenon, the time for the movement winds up being the same, regardless of the distance. Benderius said that they immediately recognized the pattern from measured steering signals, and in what he calls “a bit of a eureka moment,” they set out to determine if this patterns of human behavior could also be applied to the act of driving.

Benderius analyzed over 1,000 hours of driving data, including 1.3 million steering corrections, and found that 95 percent of them correspondent with the reaching theory. He and Markkula found that steering is not linear when the driver follows the road, but when the driver turns the vehicle’s wheel according to the special reaching pattern.

“We were able to use the theory to explain what researchers had been trying to solve for a long time,” Benderius said. “This was the answer to the previously inexplicable jerkiness in the control signal. Rather than looking upon steering as continuously following the road, steering corrections seem to be applied in a very predetermined manner.”

“The control behavior has also proven to be very natural; I saw this in an earlier study where I examined driving behavior in 12 year olds and their parents,” he added.

With this knowledge, he was able to create a mathematical model which could explain most types of observed driving behaviors – meaning that driver response to different situations could be predicted before it occurs, and could result in the development of new safety devices.

“This might completely change how we regard human control of vehicles, crafts and vessels,” Benderius said. “I hope and believe that many researchers will utilize the findings and start to think in new ways.”

“Control behavior has traditionally been studied on the basis of control theory and technical systems,” he added. “If it is instead studied on the basis of neuroscience with focus on the human, an entire new world opens up. This could push the research field in an entirely different direction.”


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