BOZEMAN -- The Western Transportation Institute at Montana State University is now home to one of the largest and most sophisticated motion-based driving simulators in the United States.
The $915,000 simulator uses real vehicle bodies mounted on a motion platform and surrounded by a 240-degree arc of projector screens to more accurately simulate the experience of being behind the wheel, said WTI's simulator manager Suzy Lassacher. Funding for the simulator came from a variety of federal and private sources.
The motion platform reproduced the feelings of movement and vibration that go along with driving in the real world. Combined with the wide field of view and a surround sound system, this means the simulator will evoke more realistic reactions from test subjects.
More realistic reactions mean more accurate and valid behavioral data for researchers to analyze, Lassacher said, and learning about how drivers react to traffic simulations is important because car crashes are the chief cause of fatal injuries in rural areas.
Lassacher said the new simulator could also help save money on road designs and infrastructure upgrades by allowing engineers to "test drive" improvements as they would appear in the real world. That could make prototyping and modeling easier and cheaper, she said.
"That will save a lot of time and taxpayer money for road improvements," Lassacher said.
Sitting inside one of the simulator's vehicle bodies -- either a Chevy Silverado pickup or Impala passenger car, though a donated Izuzu truck cab is on the way -- test subjects can see 240 degrees of computer-generated scenery, powered by six projectors, eight-foot-tall screens and several LCD monitors. Even the vehicle mirrors work, thanks to color monitors, effectively giving drivers a 360-degree view of the simulated environment.
"It's totally immersive," Lassacher said. "The wrap-around field of view makes it very realistic."
It takes almost a dozen computers to run the simulator, said Larry Cathey, a project manager and software engineer for Realtime Technologies, the Michigan-based company that installed the simulator in September.
There are several computers just for displaying the scenery. Others run the virtual dashboard, vehicle physics, motion platform and the simulated traffic. Then there's one computer for tracking the driver's eye movements and another for gathering the data used by researchers. Other computers and features can be added as needed, Cathey said.
"Our company tries to give researchers the tools that, though maybe not as visually compelling as a video game, allow them to get their studies done," Cathey said.
The new simulator can represent environments as small as a few city blocks or as expansive as a hundred-mile-long interstate highway. The driving environments are built from "tiles." These chunks of scenery are laid end-to-end in a computer, like building a model railway. The designs are limited only by researchers' imaginations and patience, Cathey said.
"It's kind of like the LEGO building block approach," Cathey said.
Adding to the realism is a fleet of computer-driven vehicles that occupy the digital roadways. These autonomous vehicles behave just like real drivers, but they can also be programmed to create traffic situations, such as crashes or near-misses, said WTI researcher Nic Ward.
The simulator's realism will help researchers get more accurate results than with WTI's smaller, lower-fidelity simulators, especially when it comes to driver reactions, Ward said.
"You want people to feel like they're moving in the real world, he said. "The motion base adds the cues people rely on in the real world to judge their environment."
In addition to the new simulator, which is housed in a garage-sized room at WTI, the institute also has a mid-sized unit that offers a 150-degree field of vision to drivers seated in a quarter of a Saturn sedan, including the driver seat and center console. WTI also has several simulators that run on desktop computers equipped with steering wheels and pedals.
The suite of driving simulators at WTI is one of the most comprehensive in the country, Ward said. The range of simulation options the suite provides allows the institute to effectively and affordably handle a wide variety of research projects.