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How does a driving simulator replicate dangerous situations?

Car Safety Pictures Can a driving simulator be useful for dangerous driving? See more pictures of car safety.
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In the year 2009, more than 33,000 people died in vehicle crashes in the United States [source: NHTSA]. If you really digest that sobering stat, you'll realize that you're taking your life into your hands every time you turn your key in your engine. Though we may feel at ease behind a wheel, dozens of variables can make any trip dangerous. Some dangers are external, such as bad weather, slippery roads and limited visibility, while other dangers drivers bring upon themselves, like alcohol impairment and cell phone use.

Other than the uniformed police officers helping to monitor our roads against dangerous driving behavior, some of the most important heroes of the highway are actually in lab coats tucked away in research facilities. And one of the most useful methods of lab research uses driving simulators, which create virtual realities that imitate real-life driving situations.

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If you've ever played a sit-down driving game in an arcade, you have a sense of what a driving simulator is. But it can be an even more immersive than that. And while video games typically imitate NASCAR or street drag races, labs use driving simulators that recreate average, albeit dangerous, driving situations.

Given the death rate on the highways, research gathered with a sophisticated, realistic simulator is invaluable. Modern technology allows researchers to control every variable of the road while observing countless details about the driver, including eye movement, delay time and even brain activity. In the safety of a controlled, virtual reality, researchers study the effects of dangerous external driving situations as well as sleep deprivation, drug and alcohol impairment and cell phone distractions, among other things. Studying this wealth of information gives clues to how to design safer roads as well as how to protect a driver from him or herself.

But driving simulators come in all shapes and sizes. Some are more sophisticated and able to create a more immersive experience than others. But researchers say that even the simplest simulators provide useful information about how drivers act in dangerous driving conditions. We'll explore the technology of driving simulators next.

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Driving simulators have evolved from flight simulators for aviation training. The simplest driving simulators resemble video games. However, an advanced driving simulator actually uses a real car, like a Ford Taurus or Chevy Malibu. The car might look and feel fully functional, but under the hood, you'll find that the engine has been replaced by a computer.

Dr. Azim Eskandarian, who works with a driving simulator at George Washington University, described how the system works. A driver who sits in the cab of a car can see a virtual world projected on a screen. The driver steers, accelerates and brakes like normal. But these actions get translated into the computer, which translates them into the virtual world. Dr. Eskandarian explains that when the driver presses on the gas, the amount of force on the pedal is electronically fed into a data acquisitions system.

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Researchers have created physics-based models that allow the computer to translate the pedal force into the right amount of acceleration in the virtual world. These models have mapped out how much pedal pressure results in how much acceleration. Each component of the engine process has a corresponding dynamic model, which is a physics-based equation that describes the relation between the input and the output. This computational process that translates vehicle control into virtual reality is called total vehicle dynamics [source: Eskandarian].

The researchers also create a virtual world to drive in. They project this world, complete with marked roads, stop signs, stop lights, pedestrians, cyclists and more, on a screen in front of the driver. Many simulators can also adjust weather, time of day and traffic.

However, even this can seem unrealistic if it doesn't "feel" like driving. In other words, it can feel like you're floating or driving on a sheet of glass rather than a real road [source: Ahmad]. The National Advanced Driving Simulator (NADS) at University of Iowa tries to fix this problem as one of the most immersive driving simulators. Omar Ahmad, the Assistant Director of NADS, explains that the car is housed in a dome hexipod with four vibration actuators and six hydraulic legs. This amounts to a 360-degree world with various degrees of vibration for imitating smooth, bumpy and gravel roads. The dome and hexipod move laterally and longitudinally on a 64 foot by 64 foot electric rail system. It even allows for 13 degrees of tilt for realistic stops, starts and turns. Ahmad explains that test subjects walk through a covered canopy to enter the dome, where they get into a typical car, which helps them suspend disbelief.

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Testing dangerous conditions on a driving simulator is safer than testing out on the road.
Testing dangerous conditions on a driving simulator is safer than testing out on the road.
©iStockphoto.com/jacus

Once you construct a driving simulator that feels as realistic as possible, as well as a virtual world to drive in, you can conduct tests to gather invaluable research. These tests can be as simple as asking a driver to text on a cell phone while handling traffic with sudden stops, pedestrians and cyclists. But some simulators can also create dangerous weather and wet roads.

Data collection can get amazingly detailed. The Center for Intelligent Systems Research at George Washington University has a driving simulator with the capability to collect data about a driver's eye movement, blink rate and blink length, and focal point of attention [source: CISR].

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Researcher Omar Ahmad explains that he has done studies with the NADS simulator that test the driving habits of drunk drivers. NADS projects a simulation of a nighttime drive home from the bar to study several groups of drivers. This includes a placebo group of those who unknowingly drink non-alcoholic drinks and groups of drivers with various blood-alcohol levels. From studying the driving habits of drunk people, such as steering swerve and speed changes, Ahmad says they are developing sensors that can be installed in cars that actually detect whether the driver is under the influence of alcohol. He claims these sensors now have 80 percent accuracy -- they identify four out of five drunk drivers. And in tests there have been no false positives -- meaning they don't misidentify any sober people as drunk [source: Ahmad].

Other than drinking, driving simulators are used to test how people drive while on various drugs or when suffering from medical or psychological issues. The U.S. National Highway Traffic Safety Administration (NHTSA), as well as various other government agencies, the auto industry and pharmaceutical companies, are known to fund driving simulator studies. The researchers at NADS were also recently awarded a study to develop sensors that detect drowsiness [source: Ahmad].

Dr. Azim Eskandarian says that beyond testing driving behavior in dangerous conditions, driving simulators allow researchers to determine the safest vehicle control functions and road designs. These can include testing seat belts as well as what font size works best on road signs.

Of course, other ways to gather this information include a closed test track or a field operational test in normal road traffic conditions. However, not only are driving simulators often more cost effective, they're obviously safer for gathering research on dangerous situations.

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Sources

  • Ahmad, Omar. Senior Team Leader at the National Advanced Driving Simulator. Personal Correspondence. Nov. 18, 2010.
  • Center for Intelligent Systems Research. “Driving Simulator Laboratory.” George Washington University. (Nov. 24, 2010).http://www.cisr.gwu.edu/lab_simulator.html
  • Eskandarian, Azim. Director for the Center for Intelligent Systems Research. Personal Correspondence. Nov. 23, 2010.
  • NHTSA. “National Statistics.” National Highway Traffic Safety Administration. (Nov. 24, 2010).http://www-fars.nhtsa.dot.gov/Main/index.aspx
  • University of Iowa. National Advanced Driving Simulator. (Nov. 24, 2010).http://www.nads-sc.uiowa.edu/

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