UI researchers use SIREN driving simulator to study driving risk factors

Surrounded by projection screens, a blue Saturn sits in a basement room in the University of Iowa Hospitals and Clinics. If you look very closely, you can see several tiny video cameras inside the car, and a glance under the hood gives a whole new meaning to the term “souped-up.”

In the space where the engine normally resides sits an array of electronic instrumentation that turns this ordinary vehicle into a high-fidelity driving simulator known as SIREN (Simulator for Interdisciplinary Research in Ergonomics and Neuroscience). These instruments allow Matthew Rizzo, M.D., UI professor of neurology, engineering and public policy, and his colleagues, to record and analyze in detail the actions and reactions of the driver. It also allows them to look for scientific answers to the kind of questions that have been circulating in the media recently such as when and how do age-related deficits make a person an unsafe driver?

“The big issue is whether there is a good way to predict who is likely to be an unsafe driver?” Rizzo said. “It is not feasible for everyone to have their own driving simulator to test patient’s driving abilities, but it is feasible to have paper and pencil tests that correlate well with simulation studies and real accident data.

“What we want to develop is a series of a few tests that are simple and reliable and that can be easily administered,” Rizzo said.

SIREN, which is uniquely positioned within UI Hospitals and Clinics, may be less well-known than the UI’s other driving simulator NADS (National Advanced Driving Simulator), which is located at the Oakdale campus and has the largest motion base of any simulator in the world. However, Rizzo and his many collaborators are extremely busy with projects using SIREN and are very excited about the results their studies are starting to produce.

“We are not interested in studying vehicle dynamics in the way that NADS can,” Rizzo said. “Rather, we use SIREN to study how drivers react and act under various conditions.”

SIREN is one tool used by the UI researchers to collect data on driver behavior and study what affects driver behavior. Multiple sensors collect information from the simulator including the positions of the steering wheel, the brake and the accelerator pedals. Cameras observe the driver’s gaze and also the driver’s feet, and a device mounted on a baseball cap worn by the driver allows researchers to track a driver’s eye movement and examine how they scan their visual environment.

The simulator’s sophisticated computer programs can generate multiple driving scenarios populated with many other vehicles. These scenarios are projected onto the screen around the simulator and provide the driver with a front and back view of an on-road scene.

The researchers can program the virtual vehicles in the simulation to drive legally or illegally. For example, a virtual car may enter an intersection illegally and unexpectedly create the potential for a crash, or a virtual car in front of the simulator driver may brake suddenly. The researchers use scenarios like these to observe how drivers react and find out if they are able to avoid potential accidents. It also allows researchers to investigate drivers’ attention to multiple obstacles that are added to the environment.

Driving studies are also conducted using an instrumented car called ARGOS (Automobile for Research in Ergonomics and Safety) that is actually driven on the roads. The UI researchers, in collaboration with Digital Artefacts, P.C., at Oakdale, also have developed a new PC-based driving simulator tool. This tool was inspired by the modern aviation information displays found in sophisticated airplanes and used by pilots to monitor the skies. Using enhanced visual cues, the tool allows excellent situation awareness on a small screen, and can be used to test drivers’ decision-making and other abilities.

In addition to these hi-tech devices, the researchers also use a range of cognitive and visual testing procedures, which allow them to analyze abilities including visual acuity, contrast sensitivity and motion perception. Neuropsychological tests allow measurement of driver attention and decision-making ability.

“It is very important that we consider all the evidence, from neuropsychological tests to hi-fi simulations, and examine what the relationships are among performances on these tests,” Rizzo said. “We want to know how performance on a low-tech, easily administered neuropsychological test is related to performance in the highly realistic SIREN simulator or to actual driving behavior measured in the ARGOS vehicle. These kinds of comparisons will help us develop simple testing methods to predict a driver’s risk.”

The researchers hope that these tests could help improve the ability to predict levels of risk in drivers and to develop methods to reduce injury.

Age is one factor that has recently been linked with risky driving. In response to the concerns about elder driver safety, the American Medical Association has recently developed a guide to help physicians assess and counsel older drivers. However, Rizzo points out that age itself does not cause risky driving rather it is conditions associated with aging such as decreased attention, decreased vision, decreased mobility and dexterity, and slower reaction times that adversely affect driving.

Although the role of age-related conditions on driving ability has become a focus of discussion, Rizzo explained that many other factors may make people risky drivers. These factors include medications, neurological disorders such as mild Alzheimer’s disease or Parkinson’s disease, brain injury from stroke or a head injury, and even lack of sleep, which is a common problem for many modern Americans.

Although it might seem very likely that drivers with brain injury or disease are at-risk, the UI researchers have evidence from SIREN studies showing that some people with mild Alzheimer’s disease can navigate fairly well and drive quite well in the simulator.

“Should the authorities penalize those drivers based on diagnosis of the disease alone, or should we monitor their performance and measure when they actually become unsafe?” Rizzo said.

Common medications used to control conditions, ranging from blood pressure and cardiac function to allergies to psychiatric diseases such as depression, can also have potential cognitive side effects such as drowsiness, which would affect driving ability. Rizzo and his colleagues intend to use SIREN to investigate how people drive when they are taking various medications. The simulator could help determine what levels and types of medications cause drowsiness that leads to unsafe driving without putting someone at risk on the road.

SIREN also has been used to safely assess the effects of alcohol and illicit drugs on driving behavior. Together with visiting Dutch scientists, Rizzo and colleagues recently found evidence that abstinent younger users of common recreational drugs of abuse, “Ecstasy” (MDMA) and marijuana, showed impulsive behavior during decision-making while driving in SIREN compared to non-drug users. “There are lots of people who have physical problems, problems with medicines, problems in relation to lifestyle and no one knows anything about how these things affect individuals’ driving,” Rizzo said. “We are can address all these issues with the simulator and our other tools.

“SIREN is an incredibly complicated system and it has taken a lot of time and effort to get it up and running, but it works and we are getting good data and we have many projects under way. It is an exciting time.”

STORY SOURCE: University of Iowa Health Science Relations, 5135 Westlawn, Iowa City, Iowa 52242-1178

CONTACT(S): Jennifer Brown, 319-335-9917, jennifer-l-brown@uiowa.edu