CHAMPCAR/CART: The Art and Science of Ergonomics

The Art and Science of Ergonomics "Human Factor" Plays Fundamental Role In Design of Mercedes Road and Race Cars

MONTVALE, N.J. (July 8, 1999) -- Whether competing in an auto race or cruising down the highway, a driver often makes split-second decisions. And long journeys, whether a 500-mile race or a 500-mile trip to Grandma's house, can tax the body and the senses.

It is vital, therefore, that the cockpit of an automobile be designed to maximize driver performance. In an automotive context, ergonomics is the design process that takes into account the driver's abilities, specific work processes and comfort. In fact, much of the art and science of ergonomics used in Mercedes-powered Champ Cars to deliver performance on the race track in the CART FedEx Championship Series is shared by Mercedes-Benz passenger vehicles, such as the high-performance AMG E55 sedan.

"Whether driving to work or driving for the checkered flag, a driver and an automobile form a functional system," said Dr. Robert P. Hubbard, professor at Michigan State University and director of the Biomechanical Design Research Laboratory. Hubbard has been studying the ergonomics, safety and biomechanics of automotive seating in production and race cars for more than 15 years. "Ergonomics is about the driver's position, movement and support inside the vehicle. It also involves vision, sound, vibration, and control cues. Ergonomics is about how people interact with the car, and how the car interacts with people -- in just about every way you can imagine."

Effective ergonomic design is therefore critical in the cockpit, and the most important elements are the seating, the steering wheel and the instrument cluster.

The Seats

"Seating, in both production and racing cars, should support the driver so he or she can effectively function with the vehicle," Hubbard said. "The driver has to be supported in healthful postures to operate the controls, see what he needs to see and be well positioned for the safety restraint systems to work."

To keep the driver confidently in place during spirited driving, the Mercedes-Benz C43 AMG and E55 AMG sedans boast high-bolstered sports seats with contouring lumbar support. In addition, the shoulder and head restraints automatically adjust to different driver heights when the seat position is changed.

"Our seats were designed for comfort and to give the driver better support on long journeys and better stability while cornering," said Karen Makris, department manager, sedans and wagons, at Mercedes-Benz USA. "The E55 has a special footrest for the left foot under the parking brake giving the driver an anchoring point on turns. The driver has greater leverage, and therefore, greater confidence."

Ergonomic seating is equally vital in a Champ Car. "A race driver nearly is lying down, doing a lot of stressful driving for hours at a time," said John Thompson, drawing-office manager for Reynard Motorsport, which builds Mercedes-powered cars for PacWest Racing, Player's/Forsythe Racing and Bettenhausen Motorsports. "Some of these high-speed corners generate four Gs, so with a 150-pound driver, that's a force of 600 pounds going sideways. We use computer-aided design models and three-dimensional mannequins to make sure our seats are designed to keep each driver comfortable and firmly fixed in the proper position. It's a lot like a sprinter's running shoes: if the fit isn't right, he won't perform at his best."

The Steering Wheel and Instrumentation

The road makes specific demands on the driver, and Mercedes has translated this ergonomically. For example, racing on an oval requires the Champ Car driver to make much smaller, more precise steering movements, while at the same time the G-force at higher speeds is tremendous. So, for oval tracks, Reynard fits a larger-diameter steering wheel into its race cars for more precise steering, and a headrest with longer sides, to make the driver comfortable on those high-speed, banked corners. The driver has less room in the cockpit to move his hands -- because he doesn't need it. Meanwhile, steering wheels for both Mercedes' road-course racing cars and its road-going passenger cousins are smaller in diameter for better maneuverability on twisty roads and crowded city streets. "Mercedes-Benz's production vehicle steering wheels are ergonomically designed for optimum comfort and control, in terms of both grip and diameter," Makris said. "In fact, they are almost one inch smaller in diameter than they were five years ago." In designing automotive interiors for both racing and street driving, it is critical to minimize the time the driver's eyes are off the road. Therefore, the most important instrument gauges on Mercedes-Benz passenger vehicles, such as the speedometer, RPM indicator and engine temperature gauge, are tinted for high visibility and positioned within the driver's primary sight lines. The instrumentation in a Mercedes-powered Champ Car takes this concept one step further -- the dashboard is located on the steering wheel itself. Designed by Mercedes-Benz's race-engine design and manufacturing arm, Ilmor Engineering, with hardware and software developed by Magneti Marelli, the wheel displays all the vital signs of the engine and the race car on an LCD screen in the center of the wheel and on brightly colored LED warning lamps along the top. This allows the driver to stay focused on the race track.

Mercedes-Benz is the Official Car of CART, and its C43 AMG sports sedan serves as Chief Steward Wally Dallenbach's Safety Car. The E55 AMG sees track duty each race weekend as PPG Pace Car for the FedEx Championship Series. This season, Mercedes-Benz provides racing engines to five CART teams, and defends its Constructor's Championship in the Formula One World Championship with the West McLaren Mercedes team.

SIDEBAR: Innovation in the Round

The steering wheel on a Mercedes-Benz Champ Car is a marvel of technology and ergonomics. Mercedes-Benz and Magneti Marelli mounted the dashboard on the wheel for better visibility of critical information. Data is accessed by scrolling through a series of six customized screens to view lap time and speed, engine RPM, various temperatures, and other important information.

"We were the first to introduce this type of dashboard in auto racing," said Giancarlo De Angelis, director of Magneti Marelli's racing department. "In fact, the entire system we've developed with Mercedes-Benz in CART is more advanced in some areas than similar systems we've developed for Formula One, and includes technology that we've used in our passenger-car systems as well."