Crashworthiness: In pursuit of a total package concept.

PORTLAND, Ore.--(BUSINESS WIRE)--Dec. 4, 1996--Unlike Europe, North America has never had an official standard for the crashworthiness of heavy-duty trucks.

Nonetheless, Freightliner Corp. continues to commit R&D resources to issues of vehicle safety, such as how to engineer cab structures to even better protect the driver and passenger space in the event of impact. From new structural concepts to airbags and seat pull-down and belt pretensioners, Freightliner is making substantive strides in crash survivability for the benefit of its customers.

Recently Freightliner built the first heavy-duty truck in North America designed and tested to meet or exceed all the criteria of the European ECE R-29 crashworthiness standard. It has made major breakthroughs in resolving the particular challenge of survivability in rollover accidents, which account for 50 percent of all heavy truck occupant fatalities.

A New High Safety Ceiling

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Vehicle crashworthiness was a cornerstone in Freightliner's development of the Century Class, the first all-new Class 8 truck in a generation. Through crash tests at the DEKRA facility in Germany, Freightliner engineers first acquired the baseline data to build a non-linear finite element crash model for computer simulations on the Mercedes-Benz Cray super computer in Germany, then later began crash testing actual prototypes of the Century Class truck at the CALSPAN Institute in Buffalo, NY and the Transportation Research Center in Ohio.

The Century Class cab was designed with reinforced A, B and C pillars to strengthen the roof top and to provide a strong "cube" for driver/passenger pod impact protection. The windshield was bonded to add strength and prevent ejection. In addition to the crash tests of complete vehicles, prototype cabs were then subjected to the full battery of ECE R-29 tests, including:

-- a pendulum test achieving frontal impact of 35,000 ft-lb.;

-- a rear impact test, equating to the impact of a 50,000 lb. payload lunging forward in a sudden stop;

-- a roof crush test, plus the first-ever use of an SAE-inspired test of diagonal load applied to the roof header, A-Pillar and side rail, not specified in the ECE R-29 standard. These tests were conducted on a Century Class mid-roof model, a 70-inch raised-roof model, and on a flat-roof daycab.

All tested Century Class models driver and passenger areas maintained survival space integrity in all of these tests -- good news for truckers and manufacturers who may have questioned whether a lightweight aluminum cab can achieve the kind of strength that European trucks have accomplished with steel construction. "We found no correlation between aluminum or steel construction and the crashworthiness of the cab," remarked Freightliner Senior Vice President of Engineering & Technology Michael von Mayenburg. "The endurance quotient is all in the design."

Safety in the SPACE-Age

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Freightliner crash tests showed that airbags in truck steering wheels by themselves do not necessarily provide the kind of support to the chest that is possible on a more vertical automobile steering wheel position.

"We realized that in addition to the greater crashworthiness of the Century Class cab, further improvement could be made to maximize the drivers survival space away from the roof, steering wheel and dash," von Mayenburg said.

In response, Freightliner teamed with its seat belt supplier, Indiana Mills and Manufacturing, to develop a new concept in driver protection dubbed SPACE -- an acronym for the unwieldy label, "Seat Pretensioner Activation for Crash Survival Enhancement." A worldwide first, SPACE can be combined with an airbag to provide a new high level of driver protection in frontal and rollover accidents.

SPACE is triggered by a crash and rollover detection sensor mounted on the floor in the seat area. The activation cylinders act on cables that replace the tether belts which normally anchor the moving part of the drivers air-ride seat to the floor. When the sensors detect a serious frontal impact or rollover, gas generators triggered in the cylinders pretension the seat belt and pull the seat itself down to keep the driver away from the steering wheel and roof structure.

"The effect," said von Mayenburg, "is to keep the drivers torso away from the steering wheel rim, to improve his relationship to the airbag, and to open additional clearance between his head and the roof. It means that head, chest, shoulder and knee excursions, plus belt forces and other injury risks are reduced."

In an inverted situation, the SPACE system pulls the seat down up to 6 inches and tightens the seat belt on the driver, providing approximately 9.5 inches more room between the drivers head and the roof of the cab. In a rollover situation, that can provide a possible lifesaving margin of safety in event of a partial roof crush.

Freightliner worked with its sensor supplier, Robert Bosch, to do a variety of driving and frontal crash tests. Rollover simulations at the one-of-a-kind Indiana Mills rollover test fixture are ongoing, in order to establish precise trigger conditions and thresholds for the SPACE sensors. Sled tests using different size dummies and out-of-position cases were run to evaluate the effectiveness of the SPACE/airbag system for a wide variety of driver sizes and conditions.

SPACE plus drivers airbag, von Mayenburg believes, provides a level of protection in heavy trucks equivalent to the best systems currently available in luxury cars in a frontal collision. "We believe our SPACE technology points the way for the trucking industry to create new dimensions of driver protection," von Mayenburg said.

A Model of Safety

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Freightliner's SPACE and airbag technologies and the new cab structure are only the beginning of some 40 new active and passive safety concepts developed to help prevent accidents and reduce injuries in the Century Class. Among them:

-- The steering column shaft collapses up to a 12-inch range to reduce the risk of impact and injury in an accident.

-- All dash-mounted toggle switches have been designed with rounded edges and flexible toggles to reduce contact injuries.

-- The seat belts are designed to be more adjustable and comfortable.

-- New bunk restraints and latches more effectively contain occupants and stored articles in event of accidents or panic stops.

-- A steeply-sloped hood achieves a new high standard of forward visibility.

-- An optional radar-based Collision Warning System warns of objects to the front or side during times of limited visibility.

-- Long-stroke brake chambers, for added reserve stopping ability, are standard for the first time in a heavy-duty truck.

-- An electronic braking system is available to shorten stopping distances and compensate for brake fade.

-- Bright amber daytime running lights are standard.

"Some years ago," said von Mayenburg, "we were challenged by The Maintenance Council of the American Trucking Associations to make a quantum leap in crashworthiness and safety. The Century Class is our answer to this challenge. We believe it sets the safety standard for a more enlightened era of trucking."

Freightliner Corp., with headquarters in Portland, Oregon, produces and markets commercial vehicles in Class 4-8 and is a member of the Mercedes-Benz AG group, the world's largest commercial vehicle manufacturer.

CONTACT: Debi Nicholson, 503/735-8535

503/735-8006 (fax)