The Story of Weak Roofs and Rollovers a Deadly Combination

posted on:
November 29, 2007

author:
Paula Lawlor

MORE INFORMATION: Roof Crush in Product Liability Claims

A critical component of the vehicle that has been overlooked for the past 34 years by both the American auto manufacturers and the National Highway Traffic Safety Administration (NHTSA) is the roof structure. The purpose of a vehicle’s roof is not merely to keep out the rain and bad weather. Accident studies show that real-world rollover accidents frequently involve extreme local stresses on the vehicle roof structure. It is the weakness of the roof structures, i.e., the lack of resistance to stresses inherent in rollovers, that allows the roof to intrude into the passenger cabin.

In 2006 alone there were 10,698 people killed and approximately 24,000 people seriously injured in rollover accidents in the United States. “Roofs in most contemporary vehicles crush extensively in a majority of rollovers where there are serious to fatal injuries. While it is clear than an occupant is safer in a rollover with a safety belt than without, public policy that increases belt use without addressing the problem of roof crush would be irresponsible.”

In 1966, Congress passed the National Traffic and Motor Vehicle Safety Act in an effort to protect the motoring public from rising injuries in automobile accidents. The legislation provided for the promulgation of minimum safety standards in the design and manufacture of all passenger vehicles sold in the United States. Pursuant to legislation, on January 6, 1971 the government proposed a minimum roof strength standard, Federal Motor Vehicle Safety Standard 216 (FMVSS 216). The intent of the roof strength safety standard was to prevent injury to vehicle occupants in rollover accidents by preventing the intrusion of the roof into the passenger compartment.

FMVSS 216 required the roof structure of the vehicle to withstand forces comparable to those experienced in a rollover. As originally proposed by the government, the test called for a hydraulic load of up to 1.5 times the vehicle’s weight to be first applied to the roof structure in the area of the windshield pillar on one side of the vehicle followed by application of the same force to the same area on the other side of the vehicle.

The application of the test force to both sides of the roof structure would simulate the sequential nature of impacts in a real-world rollover. This two-sided test, as proposed, used a 12″ x 12″ test device oriented at 10 degrees horizontally (pitch angle) and 25 degrees laterally wherein the static load was applied at the upper surface of the A-pillar until reaching a force of 1.5 times the empty weight of the vehicle. FMVSS 216 was not approved as originally proposed.

The test was modified, prior to final approval, to provide for testing of only one side. The load could be applied to either side; and both sides must be able to withstand application of the load. However, the load was not applied sequentially to both sides in the same test. The problem is that the application of the force to one side may weaken the roof structure. If the roof structure is compromised with the first application, the other side will lose strength and not be able to withstand the same amount of force, leading to the collapse of the roof structure. To verify that a roof structure is sufficiently strong enough to withstand sequential impacts as are experienced in a real-world rollover, the vehicle must be tested with sequential loads. FMVSS 216 is a static test in that the vehicle does not move during the testing.

Prior to the development of the static test, the automakers used dynamic tests to verify roof strength. One such dynamic test was the inverted drop test, in which a vehicle was suspended upside down and dropped onto its roof from 6 inches to 2 feet. It is important to note that in the late 1960s, many of the vehicles being manufactured showed serious roof collapse in inverted drop tests. The same vehicles also failed the government’s proposed two-sided static test. Their vehicles, however, could pass a standard that tested only one side with the pitch angle reduced to 5 degrees.

Internal and public records show that GM, Ford and Chrysler lobbied to eliminate the sequential testing to the second side of the roof and reduce the pitch angle for a roof strength safety standard their vehicles could pass. This test became our government standard in 1973 and it is the same standard we have today.

FMVSS 216 was first implemented in 1973 as a temporary standard to be revoked in 1977 and replaced with a rollover test rather than a static test. The rollover test proposed by the government in 1970 required that no portion of the test dummy be ejected during the rollover phase. Knowing how pitifully their vehicles were performing in dynamic roof integrity tests based on the failed drop tests, GM, Ford and Chrysler filed unanimous opposition to the government’s proposal that would have required dynamic rollover testing as part of the restraint system evaluation under FMVSS 208.

In this same time frame, GM, Ford and Chrysler designed and tested Experimental Safety Vehicles (ESV) and Research Safety Vehicles (RSV) and examined structural integrity, occupant performance and ejection characteristics in non-collision rollover accidents. These vehicles had strengthened roofs equipped with a rollbar and/or reinforced A, B and C-pillars. The result of the GM ESV in a 2-foot drop test was:

• The windshield remained in place but sheared loose along the top edge

• The right front door could be opened by hand after the test

• The maximum measured passenger compartment intrusion was 3.9 inches

The result of the GM ESV in a 30 mph lateral rollover test where the vehicle rolled 2 1/4 rolls was:

• The windshield was completely retained along all edges

• All doors could be opened by hand after impact

• The maximum measured passenger compartment intrusion was 3.8 inches

• None of the occupants extended beyond the passenger compartment

In June 1977, Chrysler concluded in Engineering Safety Committee Meeting Minutes that “the 400 additional lives saved in an RSV (Research Safety Vehicle) is the result of reduced roof intrusion.” Despite knowledge gained from the ESV and RSV programs, that a strong roof would provide occupant survival space in a rollover, GM Ford and Chrysler continued to oppose the rollover test in FMVSS 208.

The temporary static test standard which required a minimum of 1.5 strength to weight ratio (SWR) was totally inadequate and the Industry knew that it would not provide occupant survival space in the event of a rollover. In fact, in 1959 the Automotive Crash Injury Research (ACIR) department at Cornell University concluded that in rollover accidents “crushing of the top structure is also a serious problem as this effectively destroys the package compartment, leaving no room for the occupant.”

The ACIR concluded that “an auxiliary roof, supporting structure, might be added to the normal roof shell … such that the roof should support approximately 3.5 times the weight of the car without exceeding the yield point.” When ACIR made its recommendations, GM, Ford and Chrysler were each financially supporting Cornell and continued to do so for years.

Vehicle roofs designed to this bare minimum standard are designed to collapse and crush in and do not provide occupant survival space in the event of a rollover – thus 34 years of ever increasing deaths and catastrophic injuries due to the crushing of the roof into the occupant’s survival space in a rollover.

On October 22, 2001 NHTSA requested public comment to assist in upgrading FMVSS 216. On August 19, 2005 NHTSA announced its proposed rule:

• Force up to 2.5 times a vehicle’s weight is applied to a steel plate on one corner of the vehicle’s roof

• All roof components are prohibited from contacting a seated 50th percentile male dummy

• Vehicles up to 10,000 pounds are required to meet this standard

• PREEMPTION – If the automobile manufacturer meets this minimum standard and a person is killed or catastrophically injured by the roof in a rollover accident, the manufacturer cannot be sued

NHTSA also announced that the benefits of this proposed rule will be a savings of only 13-44 of the 10,000+ that die annually in rollover related accidents. There has been strong criticism of the proposed rule by safety advocates who are lobbying for a dynamic test, such as a drop test or a rollover test, rather than a static test and also believe the roof of the vehicle should withstand 3.5 times the vehicle’s weight, as is the case with the Volvo XC90 manufactured by Volvo who is owned by Ford. The added cost per vehicle to achieve a similar SWR would be somewhere between $25 and $100.

Earlier this year NHTSA decided that the next stage should be a Supplemental Notice of Proposed Rulemaking (SNPRM). An SNPRM is a notice and request for comment when an agency has made significant substantive changes to a rule between the Notice of Proposed Rulemaking (NPRM) and the final rule. The SNPRM allows the public to comment on the changes.

At an October 18, 2007 Department of Transportation oversight hearing in the Senate, Senator Mark Pryor asked if the SNPRM requires manufacturers to test both sides of the vehicle and Transportation Secretary Mary Peters said she believes it does. The SNPRM has now been presented to the Office of Management and Budget (OMB) and is expected to clear OMB on January 15, 2008 and to be published on January 30, 2008. The comment period will end March 28, 2008. The legal deadline for the final rule is July 1, 2008.

In 2006 the American College of Surgeons (ACS) deleted Rollover as Triage Criterion. According to NHTSA figures, the 2006 comprehensive cost of the 10,698 fatalities, 23,793 serious injuries and 183,207 minor and moderate injuries is conservatively $46 billion. With this number of deaths and serious injuries occurring it is certain that in many of the rollover accidents every minute counts. How is it then that the American College of Surgeons has abandoned these victims of rollover in their system of sorting patients according to need for treatment? The bigger question is, “Who is taking care of the people?”

The proposed FMVSS 216 is not a dynamic test and ignores most factors that are important in a real-world rollover. The FMVSS 216 static test is run to an inadequate load level, and inadequate load angle and to an insufficient crush level. This static test relies on the glass for roof strength, does not record injury levels, does not evaluate occupant survival space, does not evaluate the restraint system and does not subject the vehicle to real-world forces and crush levels.

The new roof strength standard MUST SAVE THOUSANDS OF LIVES ANNUALLY. Accident analyses show real-life rollover accidents frequently involve extreme local structural stresses on parts of the vehicle structure, therefore Mercedes-Benz conducts rollover and roof-drop tests on its vehicles. The new standard should include a dynamic test such as a drop test or a rollover test utilizing a test dummy(s).

The inverted drop test does not rely on the glass for roof strength, considers occupants (test is run with a test dummy), can record injury levels, evaluates occupant survival space, evaluates the restraint system and subjects the vehicle to real-world forces and crush levels. An inverted drop test is easy to conduct, it is very repeatable and it produces a vast amount of meaningful information that relates to vehicle performance in real-world rollover accidents. The inverted drop test has been used by auto manufacturers since the 1960’s. NHTSA has stated that the inverted drop test is noted to produce deformation patterns similar to what is observed in rollover tests and real-world rollover collisions.

NHTSA concluded that the inverted drop test has merit in its usage, realism and repeatability in evaluating roof crush. Most European manufacturers already use inverted drop testing to evaluate the rollover performance of their vehicles. They design their vehicles to withstand the forces of an inverted drop test and as a result, European vehicles such as the Volvo XC90, the Mercedes M Class and others provide superior occupant protection during rollovers. Mercedes even goes so far as to call the inverted drop test one of its most important crash tests.

Two-sided static testing – each test should be conducted to the full 5 inch depth and maintain the SWR Pitch angle – An examination of details of the same 273 National Accident Sampling System (NASS) rollover crashes from accident years 1997-2000 that NHTSA used to develop and support an amended FMVSS 216 revealed, “virtually all had major damage over an A pillar and a substantial majority had front fender damage indicating that forward pitch in at least one impact was roughly 10 degrees.”

It was concluded that “A realistic test of roof crush resistance, whether quasi-static or dynamic, must be conducted at a pitch angle of at least 10 degrees.” Angle of platen – If the SNPRM does include a two-sided static test, that is two sequential tests on the same car body, it is important to note that the lateral and vertical component of the load angle is significant as it influences the collapse of the roof into the survival space. In 1983 General Motors’ engineer Ivars Arums designed static tests to simulate real world rollovers for the purpose of reducing roof deformation in order to keep the glazing intact which would in turn prevent ejections.

These tests were performed at lateral angles of 49 – 55 degrees on the roof as opposed to the 216 angle of 25 degrees (a more vertical force) on the roof, chosen specifically by Arums after he analyzed real world accidents and realized that roof to ground contact occurred at lateral angles of close to 52 degrees. And Arums tested the same vehicle statically on both sides of the roof at an angle of 45 degrees. Arums’ lateral roof crush tests results demonstrated a 33% reduction in roof strength as compared to the results of the same vehicle when tested according to FMVSS 216.

Load level – The two-sided static test must also have a sufficient loads in each of the tests in terms of multiples of the gross vehicle weight to be able to replicate the deformations occurring in real-world rollover accidents. It is important that the roof of the vehicle withstand a load level of 3.5 times the vehicle‘s weight on each side of the vehicle roof (driver’s side as well as passenger side of same vehicle) to be sufficient to provide occupant survival space. It is critical that the tests are run to the full 5 inch depth.

Stopping the test on the first side when it reaches the designated SWR (at a depth of 3 inches or so) would have no effect on the other side. Yet in real-world rollover accidents, roof contact with the ground on one side effects the geometry of the other side of the roof. Misconception that partial and full-ejection in rollovers is not related to roof crush Roof deformation can not only lead to roof collapse and “crush” over the occupant’s survival space but it is also the leading cause of full and partial ejection.

Roof failure affects the geometry of the safety belt system and can result in the side impact air bags not providing effective protection. The loss of structural integrity can result in the deforming roof directly exposing the occupant to contact with outside hazards and is also the principal cause of glass breakage which then allows partial and total ejections through the vehicle’s now glassless openings. These critical issues have been totally and purposefully ignored by both NHTSA and the auto industry in all their reports and analysis of the lives lost and therefore the potential lives saved by an adequate roof strength standard.

ESC – electronic stability control. NHTSA has recently mandated ESC as standard equipment in all SUV’s in the near future. ESC will only be partially effective in preventing SUV rollover accidents. There will continue to be many thousands of rollover accidents annually which will continue to produce thousands of deaths and catastrophic injuries annually if a strong roof strength standard is not immediately implemented.

In May 2003 the United Nations Ambassador of Oman, Fuad Al-Hinai, introduced a resolution on the global road safety crisis. He addressed the United Nations General Assembly stating that road accidents caused 1.2 million deaths and injured 10 to 15 million people each year. By 2020, road traffic deaths would account for 3.3 million deaths globally, with more than 90% occurring in low and middle-income countries. According to World Health Organization he said, road traffic accidents caused 2.8% of all global deaths.

The annual cost of road traffic deaths was a staggering $518 billion. And Ambassador Al-Hinai made the point that the thousands of deaths caused by road accidents per year did not receive the media attention of a single aircraft crash.

On April 14, 2004, for the first time ever, the U.N. General Assembly devoted a session to the global road safety crisis. U.S. Transportation Secretary Norman Mineta addressed the U.N. General Assembly, “We need not accept morbidity as the price of mobility anywhere in the world.” Mineta said the annual deaths a year in the U.S. (Which in 2004 was 42,636) was unacceptable. Mineta told the U.N. General Assembly, “President George Bush’s Administration has established a goal to further reduce the traffic death rate by a third by the year 2008.”

At the time the annual mileage death rate in the U.S. was 1.5 deaths for every 100 million vehicle miles traveled. By 2006 the annual mileage death rate in the U.S. was 1.42 deaths for every 100 million vehicle miles traveled and the annual road deaths increased to 42,642. What plan of action is in place for the annual mileage death rate to plummet to 1 by 2008? Wishing isn’t good enough, there must be a concrete plan.

On October 27, 2005 the United Nations designated the third Sunday in November as a day of remembrance for those that die and are injured due to road crashes and called on nations globally to improve road safety. On June 20, 2007 Senator Christopher Dodd [D-CT] introduced a bill at the 110th Congress: S. Con. Res. 39: A concurrent resolution supporting the goals and ideals of a world day of remembrance for road crash victims. Co-sponsors of the bill were: Senator Thad Cochran [R-MS], Senator Frank Lautenberg [D-NJ], Senator Carl Levin [D-MI], Senator Richard Lugar [R-IN] and Senator Robert Menendez [D-NJ].

This bill was passed in the Senate on October 4, 2007 encouraging the people of the United States to commemorate a world day of remembrance for road crash victims with appropriate ceremonies, programs, and other activities. The bill now goes to the House. The designated day this year falls on November 18th.

Senator Mark Pryor [D-AR] is Chairman of the U.S. Senate Commerce Committee Subcommittee on Automobile Safety and Senator Daniel Inouye [D-HI] is Chairman of the U.S. Senate Committee on Commerce, Science & Transportation. Both are responsible for providing guidance and oversight to the National Highway Traffic Safety Administration so that it can meet its mission to save lives, prevent injuries and reduce economic costs due to road traffic crashes and can meet its vision to be a global leader in motor vehicle and highway safety.

Either of these Senators is in a position to call a congressional hearing for the purpose of enacting legislation for strong vehicle roofs. There is no other issue in our country that involves as many deaths annually as the number of deaths in rollovers. I encourage you to write to your Senators and Congressmen requesting they communicate with Senators Pryor and Inouye their desire for a congressional hearing to enact legislation for strong vehicle roofs that does not include preemption.

I have personally found that most of the politicians in Washington, DC are uninformed on this issue of roof crush in rollovers. The question once again, “Who is taking care of the people?” And the answer is, the people – people like you and me that see a problem and take the time to take action with letters and petitions and phone calls and personal meetings addressed to the key people in power to correct it.

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