The documents described below, listed and summarized in chronological order with new postings on top, may be accessed in .pdf format by clicking on the links highlighted in each summary. (If you do not have Adobe Acrobat Reader, which is required to view the documents, click here for a free download.) Additional documents in the Rollover Collection will be made available on this website in the future.

Documents Posted November 15, 2005

The following historical documents were posted to the Motor Vehicle Hazards Archive Project on-line Rollover Collection on November 15, 2005. (Documents posted in the Collection earlier will be found at the conclusion of this posting.) These documents address the issue of roof strength and roof crush, which at the time of this addition is the subject of a National Highway Traffic Safety Administration rulemaking proceeding to amend Federal Motor Vehicle Safety Standard No. 216, setting static-test performance levels for roof penetration under simulated impact conditions.

To learn more about this rulemaking, go to the Department of Tranportation to see a summary of the proposed rule with a link to the PDF copy of the rule and links to other docket documents, including comments from advocacy, research and industry parties. For a complete look at all comments on the subject filed with the agency on this matter in recent years, click here and drill down, using “NHTSA” for agency and “roof crush” for subject.

The history of manufacturer and regulatory policies and practices concerning the strength of roofs and the role that their deformation plays in rollover injuries is of critical importance to injury control, particularly as Sports Utility Vehicles, with their increased rollover tendencies, have substantially increased their share of the passenger motor vehicle population and their proportion of rollover injuries to occupants. The documents posted here are drawn in part from the internal records of Ford Motor Company, a major manufacturer of passenger vehicles, including highly popular SUV models, concerning roof strength. (Ford internal documents are marked with an asterisk.) They were produced by the company in the discovery phase of litigation. Other documents posted below are from non-discovery sources.

*1960 ­ In a rollover test of a 1960 Falcon, “the roof structure proved inadequate” due to the amount of crush it experienced. “The front of the roof collapsed and the windshield and back window left their position on the first roll…the tempered glass used in the Falcon shattered completely and allowed the dummy’s arm to hang out of the opening and be torn off.” During the 1960s, according to crash test reports produced in the litigation, Ford carried out numerous roll tests, many of which produced roof crush “most often as a result of a collapse of the vehicle’s ‘A’ pillar,” according to an attorney involved in the discovery.

1967 ­ NHTSA publishes an Advanced Notice of Proposed Rulemaking asking for public comment on a broad range of issues that might be addressed in future motor vehicle safety standards.

*1968 ­ In an internal memo titled “Roof Strength Study, ” dated July 8, 1968, a Ford engineer extensively reviews available data and concludes that “a significant number of accidents involve roof damage” and that “people are injured by roof collapse. The total number of nationwide deaths cannot be estimated but it is a significant number.” Although roof damage has “little effect upon the severity of injuries sustained by unrestrained occupants,” the use of upper torso (lap-shoulder) belts will have “a more pronounced effect on occupant injuries… It is obvious that occupants that are restrained in upright positions are more susceptible to injury from a collapsing roof than unrestrained occupants who are free to tumble about the interior of the vehicle. It seems unjust to penalize people wearing effective restraint systems by exposing them to more severe rollover injuries than they might expect with no restraints.”

The memo recommends a minimum roof strength that will withstand a loading of twice the weight of the vehicle. “Existing roof strength is in the range of .5 to 1.5 times the weight of the vehicle.” (The present Federal standard, in effect since 1973, applies a loading of 1.5 times; the proposed standard would set the figure at 2.5 times. It would take effect no earlier than 2009.)

1968 ­ General Motors comments to NHTSA’s 10/14/67 ANPRM, dated July 22, 1968, describe, in an attached paper by Klove and Ropers, GM work involving dynamic rollover tests of roof deformation, and the repeatability problems found with such tests; development of a static test by Fisher Body, and GM’s development of improved header-area occupant impact management designs to decrease injuries from occupant contacts with the roof area above the windshield. A cover letter calls for a technical conference of auto companies to be convened by NHTSA to consider occupant impact protection issues.

1968 ­ In comments to NHTSA’s 10/14/67 ANPRM dated July 22, 1968, the Automobile Manufacturers Association states, “A review of available National Safety Council and ACIR [Automotive Crash Injury Research program] data fails to indicate a roof intrusion causal relationship to occupant injury.” Rollover accidents, it states, “are so random and varies that loading or force direction seems to be completely unpredictable.” It terms a dynamic roof-crush drop test as “not essential” ­ “a slow rate of loading would result in a more practical and repeatable evaluation of roof structure strength.”

1968 ­ Ford comments to NHTSA’s 10/14/67 ANPRM of July 22, 1968 to NHTSA state that there is “no evidence related to occupant injury to suggest the need for a standard to limit intrusion from front, rear or roof exterior impacts…the basic issue to be resolved is whether a simple limitation on intrusion will result in a reduction in injury or death or whether the requirements for structural performance of a vehicle must be developed in terms of the effects of the forces transmitted to the occupant.”

*1969 ­ A May 20, 1969 safety engineering evaluation concludes that “the most effective way of reducing roof crush” is by “increasing the ‘A’ pillar moment of inertia at the belt line.”

*1970 ­ A February 25, 1970 Car Body Systems presentation notes that the Department of Transportation is working on “a consumer information standard for rollover protection.” It states that GM products “tend to have greater potential for providing roof crush strength” than Ford products, and that Ford’s “new roof designs all show increased rake angle and reduced minimum moments of inertia, resulting in reduced capability to provide roof strength.” It concludes that “Ford Motor Company designs are making it increasingly difficult (and presumably more costly) to achieve the objective level of roof crush strength.”

*1971 ­ On January 6, 1971, NHTSA issues its Notice of Proposed Rulemaking to establish FMVSS 216. It states that a recent analysis indicates that 1400 people were killed in 1969 “by impact with roof structures in rollover accidents. Roof intrusion would have been sufficient in many of the cases for the roof to have struck the head of a properly restrained occupant.” It proposes a static loading compliance-test requirement of 1.5 times the vehicle’s weight (1.5 G’s) “or 5,000 pounds,” whichever is less. The loading would be applied above the A-pillar on both sides of the roof during the test. It proposes an effective date of January 1, 1973 for the standard, which would apply to passenger cars but not so-called multipurpose vehicles. (Ford produced a copy of the NPRM from its files during discovery.)

1971 ­ Ford, at its request, meets with NHTSA officials to press its position that “available evidence does not suggest that existing roof structures contribute significantly to occupant injury through collapse in rollovers” and to argue for a standard weaker than NHTSA’s proposal and a later effective date.

*1971 ­ In a Safety and Emissions Program discussion paper dated March 22, 1971, and evaluating NHTSA’s Notice of Proposed Rulemaking in FMVSS 216, NHTSA’s estimate of 1400 roof-structure impact deaths in 1969 is disputed. “Roof intrusion will not cause death of properly restrained occupants unless the roof is violated by a ‘fixed object’ ­ a tree, abutment, etc.” The authors “have seen no evidence to conclude or correlate roof strength with occupant safety/injury.” Among the paper’s conclusions are that current (1971-72) Ford vehicles “will not meet the Government proposal of 1.5 times the empty weight of the vehicle, nor will “current 1973 Ford-Mercury” models. “Future new model programs for 1974 and beyond do not have a direction other than to meet current Ford proposal of 1 ‘G’ and, therefore, do not meet current Government proposal.”

To meet the government’s proposed requirement on a 1973 Ford-Mercury, the paper says, “Depending on changes required in ‘A’ pillar, windshield header, roof rails and ‘C’ pillars, the cost increase over 1971-2 would be $9.00 to $16.00 and over 1973 would be $5.00 to $12.00 while the weight increase would be 25 to 53 pounds…” The paper recommends that Ford seek NHTSA adoption of a weaker standard reflecting Ford’s current in-house standard and the roof crush performance levels of its products.

1971 ­ Chrysler files its response to the NHTSA Notice of Proposed Rulemaking on March 30, 1971. Although it states that “the test requirements contained in the notice are reasonable for a proposal for a minimum standard,” it states that Chrysler cannot “reconcile or accept the conclusions drawn from the fatality statistics referenced in the preamble to the Notice.” Chrysler asks that the standard require a loading test on only one side of the roof.

*1971 ­ On April 4, 1971, Ford responds to NHTSA’s Notice of Proposed Rulemaking in FMVSS 216 by disputing the agency’s injury estimates, urging that the final standard be substantially weaker than that proposed by NHTSA (including a crush test loading requirement of one times the vehicle weight), and putting off the effective date by three years, until 1976. In an attachment, a Ford engineer who earlier released a study showing “a small but statistically reliable increase in the degree of occupant injury as the amount of roof crush increased for non-ejected occupants of rollover accidents” states that on the basis of new data, “nothing conclusive can be said about the mechanism of a roof crushing into an occupant and causing fatal injuries because such an instance was not found in these data. It can be said, however, that the data do not implicate top intrusion as an automotive safety problem.”

1971 ­ General Motors files its response to NHTSA’s proposed rulemaking on April 5, 1971. “To help reduce the possibility of head and neck injuries in the event of occupant contact with the roof in any type of accident, most 1971 General Motors passenger car models incorporate a new double steel roof with a contoured inner panel.” GM notes that it has developed a static test procedure “similar to that proposed by the Administration. Although we know of no safety relationship correlating such a laboratory procedure with occupant protection in actual rollovers, we have found it to be a useful development tool in evaluating the effects of structural changes.” It asks that the test loading be applied to only one side of the roof.

1971 ­ The Automobile Manufacturers Association files a response stating that it can “find no causal relationship between the amount of roof deformation and the injury status of the occupants in field accidents.” It attaches a table that “demonstrates that major deformation can occur with little or no injury; and fatal injuries can occur with no deformation.” A reference in NHTSA’s rulemaking proposal “suggests that if the individual were properly restrained’ the level of fatalities allegedly could be reduced to approximately 1.5% or 700 deaths, based on 1969 accident data. Even these 700 deaths would not necessarily be eliminated if there were no roof intrusion since occupants to not remain in an upright position and might impact other vehicle interior surfaces.” AMA says its “questions whether there is a safety need for a standard on static roof strength that is not correlated with occupant safety.”

*1971 ­ A Ford memorandum of April 27, 1971 compares the company’s response to NHTSA’s rulemaking proposal to the responses of General Motors, Chrysler and American Motors. It reports that Ford sought greater weakening of the proposed standard than the other three manufacturers in a number of areas including, for example: “In relation to the minimum strength requirement, Ford recommended that it be equal to vehicle curb weight, General Motors 1 ? times curb weight, Chrysler 1 ? times the unloaded vehicle weight and American Motors, 1 ? times curb weight…” All the manufacturers and the Automobile Manufacturers Association, it says, “reiterated the complete lack of accident data to support the Administration’s position, ‘…deaths and injuries due to the intrusion of the roof…’”

*1971 ­ NHTSA issues its final rule in FMVSS 216 on December 8, 1971, to take effect in August 1973. It includes the 1 ? times weight requirement but imposes the test on only one side of the roof. It also states that manufacturer responses to the rulemaking proposal “suggested that there is no significant causal relationship between roof deformation and occupant injuries in rollover accidents. However, available data have shown that for non-ejected front seat occupants in rollover accidents, serious injuries are more frequent when the roof collapses…” (Ford produced this copy of the final rule from its files during discovery.)

*1973 ­ Pennsylvania’s Secretary of Transportation, in a filing with NHTSA dated June 25, 1973, provides data concerning 123 cases that “involved roof deformation of a vehicle roof structure due to the roof structure making contact with the ground.” Severe deformation resulted in a greater number of deaths than moderate deformation, the filing states. “From this comparison, we believe that it is preferable to prevent severe deformation of roof structure of the vehicle. This can be accomplished by the establishment of a rollover standard which would provide for stronger roof structures and/or rollbar structures. We understand that such a standard is in the discussion stages currently and recommend that action be taken to establish it as soon as possible.” (Ford produced a copy of the filing from its files in discovery.)

1978 ­ Under the title “Unwarranted Delays by the Department of Transportation to Improve Light Truck Safety,” the General Accounting Office (now Government Accountability Office) criticizes DOT-NHTSA for failing to give “the same attention to light trucks as it has to passenger cars. Consequently, the occupants are not being afforded a comparable level of safety.” Among the many FMVSS areas where GAO notes NHTSA failures to cover light trucks, it says of FMVSS 216: “It applies only to passenger cars. There have been no attempts by the Safety Administration to extent its application to other vehicles…The Safety Administration believes more data is necessary before any action can be taken. However, the agency has not taken action on the basis of data currently in its files.”

GAO notes NHTSA’s stated intention that FMVSS 208, the passive restraint standard, “will include a rollover protection requirement which should reduce the need for a roof-crush resistance standard.” But, GAO comments, “unless standard 208 is modified, it may have no impact on the need for a roof-crush resistance standard. The Safety Administration allows the rollover restraint requirements to be met by the installation of a lap belt. Thus, the manufacturers need not test vehicle roof strength to meet the requirements of standard 208.” (NOTE: The rollover protection provisions of FMVSS 208 have never been put into effect as requirements for new vehicles.]

1982 ­ NHTSA engineers publish a paper “Light Vehicle Occupant Protection ­ Top and Rear Structures and Interiors,”, (SAE 820244), finding that “in 1979 approximately 9 percent of the [35,000] light vehicle occupant fatalities occurred as a result of head impacts to A-pillar and/or roof edge structures. Head to roof interior impacts accounted for more than 3 percent of the total occupant fatalities, and [sic] the majority of which occurred during rollover accidents.” (NOTE: The copy of this paper produced by Ford in discovery was too faint to reproduce effectively. The copy reproduced in the link from this item is a clean copy from the Motor Vehicle Hazards Archive.)

1987 ­ “Light Truck and Van Safety”, a wide-ranging report to Congress from NHTSA dated May 1987, addresses the question of extending passenger car safety standards such as FMVSS 216 to light trucks. Such extensions “may not result in safety improvements when manufacturers already comply on their own. In such cases, without evidence of industry ‘backsliding,’ the issuance of standards only results in increased government costs (due to rulemaking and enforcement efforts) and increased industry costs (due to paperwork and compliance certification requirements) without any improvement in safety since the vehicles themselves will not be manufactured differently. Indeed, such an approach (‘memorializing’ through regulating industry practice) can have negative safety effects as it could result in a reduced incentive to produce greater safety in the future due to the added regulatory costs involved when the agency incorporates the safety improvements into the standard.” The report informs Congress that the agency “plans to conduct a series of dynamic rollover tests aimed at evaluating the safety aspects of roof structures and ejection prevention.” (p. 20)

1989 - A preliminary regulatory evaluation of possible rulemaking to extend the coverage of FMVSS 216 to light trucks is published by NHTSA. It states that major manufacturers, including Ford, GM, Chrysler, American Motors, VW, Suzuki, Subaru, Nissan and Toyota, have told the agency that virtually “all of their light trucks did comply” with FMVSS 216 already, “either by testing or through engineering judgment.” Data indicate that light trucks “experience higher levels of intrusion but this does not translate to higher levels of injury. This may result from differences in passenger compartment configuration which allow more headroom in light trucks.” The evaluation concludes that “roof crush does play a role in injury to persons who are not ejected from the vehicle” in rollovers. “There does not appear, therefore, to be a need for a standard that is more stringent than that which is applicable to passenger cars,” but in applying the standard to light trucks, “to maintain a standard that is equivalent to that of passenger cars, it may be necessary to eliminate the 5,000 lb. ceiling that is currently allowed for passenger cars… Since nearly all passenger cars comply at forces that are 1 ? times their curb weight, allowing light trucks to comply at the 5,000 lb. ceiling would essentially be establishing a weaker standard for trucks than for cars.”

1989 ­ In a Notice of Proposed Rulemaking dated November 2, 1989, NHTSA says it is considering extending the provisions of the roof crush standard, FMVSS 216, to “light trucks,” meaning “vans and other multipurpose passenger vehicles (MPVs), as well as trucks and buses, with a gross vehicle weight rating of 10,000 pounds or less,” which would include SUVs. It notes that sales of light trucks “are increasing and that those vehicles are being used increasingly to transport people instead or in addition to property.” Updated data indicate “that in rollover crashes the multipurpose passenger vehicle fatality rate was 137 percent (1987) and 98 percent (1988) above the average for light trucks and passenger cars combined.” NHTSA says it that the benefits of measures to prevent ejection in rollovers, such as belt use and improved glazing, “will be fully realized only if adequate protection is provided to guard against the collapse of the passenger compartment roof in a rollover crash.” The proposed rule would eliminate the test weight ceiling of 5000 pounds when applied to light trucks. Comments on the NPRM are due by January 2, 1990. The standard’s proposed effective date is September 1, 1991.

1989 ­ According to a notice published by NHTSA in the Federal Register on November 30, 1989 an agency evaluation shows that, “The shift from hardtops to pillared cars, in response to Standard 216, saves an estimated 110 lives per year.”

1989 ­ Ford files a response to NHTSA’s 10/2/89 NPRM on December 12, 1989, stating that while it supports the proposal, it “recommends that requirements of current standard 216, including the 5,000 pound load limit, be extended to all light trucks (except school buses) with a GVWR of 8,500 pounds or less, and a UVW of 5,500 or less.” The company says it “believes that all of its light trucks with a GVRW of 8,500 pounds or less meet or exceed the agency’s proposed requirements.”

1989 ­ Chrysler files a response to NHTSA’s 10/2/89 NPRM on December 21, 1989. The company “has been incorporating the necessary body structure into our pickups, vans and sport/utility vehicles to meet to the passenger car roof crush resistance requirements…voluntarily, not because of a safety need” but because of “a very high likelihood that the current requirements of FMVSS 216” would be extended to light truck vehicles. “Now, however, the agency apparently has changed its position and is proposing requirements which are substantially more stringent without quantifying a need for this higher level of performance.” It appears, Chrysler says, that “the agency believes that the principal cause of non-ejection fatalities in light truck rollovers is occupant compartment roof crush, and that the current passenger car requirements are inadequate to deal with this. To our knowledge, neither the agency nor any else has published data or information to substantiate that position.” Chrysler says it “cannot meet this [proposed] requirement without extensive redesign and retooling, which will require at least two years leadtime following the publication of the final rule. Therefore we would not be able to comply by the proposed September 1, 1991 effective date.”

1990 ­ General Motors files a response to NHTSA’s 10/2/89 NPRM, “In spite of numerous studies which have demonstrated the lack of a causal relationship between roof crush and occupant injury in rollover accidents,” it says, “GM recognizes that there is a common misconception that roof intrusion is a cause of injury in vehicle rollovers.” It says that while GM “does not oppose the application of the current passenger car requirements of FMVSS 216 to ‘light trucks’ with a GVWR of 8,500 pounds or less…GM does not support the application of FMVSS 216 to ‘light trucks’ with a GVWR in excess of 8,500 pounds, nor do we support the elimination of the current 5,000 pound test for limit for ‘light trucks.’”

1991 ­ A final NHTSA rule dated April 17, 1991, extends FMVSS 216 to light trucks, as proposed in the 10/2/98 NPRM. The rule allows no limit in the test force for light trucks, thus eliminating the 5,000 pound limit allowed for passenger automobiles. However, it lowers coverage of the extended rule to vehicles of less than 6000 pounds GVWR. The effective date is pushed back two years, to September 1, 1993.

Documents posted October 25, 2005

1959 Study of Human Kinematics in a Rolled-Over Automobile, an early research project sponsored by Liberty Mutual Insurance Co. and carried out at Cornell Aeronautical Laboratory (CAL), examines ìthe kinematics of the human body in relationship to the interior of the car body with when a roll-over condition was imposed upon the vehicle. The project uses ìexperimental tests, including a roll-over simulator, and time-motion techniques. ìUnder practically all test conditions, the passengers heads struck some part of the interior of the car body before the car had rotated 90 degrees. 68 pages

1968 In a Study of Rollover in Rural United States Automobile Accidents, a researcher at the Automotive Crash Injury Research unit of Cornell Aeronautical Laboratory reports, on the basis of sampled rollovers, that ìthere is a strong correlation between rollover frequency and vehicle dimensions: rollover increases as car size shifts from heavy, wide track, low vehicles to light, narrow track, high cars, the ingredients of a controversial formula for determining rollover propensity that was later known as the Static Stability Factor. 11 pages

1973 The National Highway Traffic Safety Administration (NHTSA) publishes an Advance Notice of Proposed Rulemaking on Rollover Resistance. NHTSA says it is considering the issuance of a safety standard that would specify minimum performance requirement for the resistance of vehicles to rollover in simulations of extreme driving conditions in attempting to avoid accidents. At this time the agency is primarily concerned with vehicle rollovers on smooth, dry pavement. The agency invites comment on the proposal. Two pages

1973 American Motors, the maker of Jeep vehicles, files a comment with NHTSA objecting to the agency's plans to move forward with a rollover standard. It does not believe that a demonstrated need exists, in terms of highway safety, for regulation of the tendency for a motor vehicle to roll over. In fact, a vehicle's inherent tendency to roll over does not appear to be a primary factor to the occurrence of vehicle rollover during a vehicle crash situation. However, adding that Jeep vehicles are designed for off-road as well as on-road usage, AMC states:

The most significant difference between on-road and off-road vehicles (in terms of rollover resistance) is the ratio of center of gravity height to track width. Considerations for ground clearance and mobility require that this ratio for an off-road vehicle must be significantly greater than that for an on-road vehicle. This means that, on an absolute grading scale, it is likely that the inherent tendency for rollover would be greater [for a Jeep vehicle] than that of a typical passenger car. Three pages

1973 On behalf of its members, the Motor Vehicle Manufacturers Association of the United States (MVMA) files a comment with NHTSA objecting to plans for a rollover standard, for which it says there is an absence of safety justification. MVMA says that data concerning on-the-road rollovers are inadequate to validate any overturning test procedureî that NHTSA might propose or require. It cites work by the University of Michigan Highway Safety Research Institute in support of its position. 20 pages

1977 A comprehensive summary of past rollover literature is published by NHTSA. Rollover Accidents: A Bibliography, addresses literature acquired since the establishment of NHTSA concerning motor vehicles involved in rollover accidents. It is comprised of NHTSA contract reports, reports of other organizations concerned with highway safety, and articles from periodicals in related fields. 116 pages

1979 American Motors internal memoranda and calculations, later disclosed in Jeep rollover injury litigation, show the extent of knowledge by company engineers and management of the Jeep CJ's vulnerability to rollover under on-road driving conditions. The materials include a table showing that the Jeep CJ7 hardtop requires only .75 Gs of lateral force to roll, compared with considerably higher values for other vehicles such as the 1979 Jeep Wagoneer (.99 Gs) and the 1979 Ford Bronco (.93 Gs). The materials refer to an improved CJII design which might incorporate design changes that, while ìnot a cure for rollover would make a significant improvement in the CJ. Eight pages

1979 Mr. Edward Barrows of San Jose, CA, files a petition with NHTSA asking for agency action to remedy the Jeep CJ5's instability and its overall design, with particular attention to its totally inadequate roll bar, which gives the driver and passengers a false sense of security. He describes the death of his seat-belted 15-year-old son in a CJ off-road rollover, as well as other reported CJ rollover deaths and injuries. 29 pages

1980-84 A Summary of Rollover Studies, IIHS Demonstration Project, 1980-84 describes rollover-related research conducted or sponsored by the Insurance Institute for Highway Safety during that period. 46 pages

1980 The first major study of its kind, On-Road Crash Experience of Utility Vehicles is a comprehensive examination of utility vehicle fatal and non-fatal crashes by researchers at the Highway Safety Research Institute (HSRI) of the University of Michigan. Major conclusions are that: utility vehicles experience a rollover rate 5 to 11.5 times higher than passenger cars; the Jeep and pre-1978 Bronco overturn at least twice as often as the Blazer; rollover and ejection rates in open-cab vehicles appear to be major fatal injury factors; death and injury rates are about twice as high in Jeeps as in Blazers. The study findings raise serious questions concerning the safety and stability of these vehicles. Included in the studyís sources are 111 product liability cases involving rollovers of utility vehicles. 260 pages

1980 NHTSA denies Mr. Barrow's petition. In summary, our findings do not indicate the presence of a potential safety defect in the design or manufacture of the CJ-type vehicle stability or Jeep-approved roll bar integrity. Off-road driving is extremely hazardous and requires the driver to be experienced with the capabilities of the vehicle, the driving technique required in off-road driving, and the terrain on which the driving is to be done. No mention is made of the CJ's possible rollover hazards during on-road driving, for which the vehicle was in widespread use. 40 pages

(Included in NHTSAís defect denial file is a letter to the Federal Trade Commission forwarding the file per your request. Subsequently the FTC would initiate action against American Motors for portraying and promoting risky driver behavior in CJ advertising materials.)

1980 The Motor Vehicle Manufacturers Association (MVMA) attacks the HSRI study. In Critique of Utility Vehicle Research Report, the industry group voices ìconcern regarding the quality and the biases of the study. The thrust of the critique is that because utility vehicles (such as Jeep CJs) are ìa distinct class of vehicle designed for use both on rough terrain and on public highways, their stability and rollover proneness should not be compared to those of passenger cars. But the critique does not deny that such vehicles ìhave different stability characteristics than general use passenger vehicles. 8 pages

1980 The Insurance Institute for Highway Safety (IIHS) publishes an extensive report of its research into rollover problems of the Jeep CJ, including details of CJ rollover stability tests carried out for the Institute earlier in the year. A summary report titled Serious Rollover Problems Found in Jeep CJ-5 Utility Vehicles includes descriptions and photos of the rollover stability tests; reference to 37 court cases involving rollovers of CJ Jeep models that ìreportedly involved at least 15 fatalities and 31 injuries, and analysis of very heavy human and property damage losses associated with the Jeep CJ-5. IIHS also releases video excerpts of its CJ rollover tests. 11 pages

1981 American Motors materials prepared for an in-house meeting on CJ modifications describe customer problemsî as including Rollover: Increase track, lower c.g., improved sway bars. (Documents produced in litigation.) Seven pages

1981 An Ohio Supreme Court decision in Leichtamer et al. v American Motors upholds compensatory and punitive damages against the manufacturer for injuries sustained in the off-road rollover of a Jeep CJ-7, finding among other things that the vehicle's roll bar, although rugged in appearance, did not provide the protection indicated by the company's marketing claims. It cites Jeep advertising that groundlessly promoted a safe image of the vehicle for off-road use. 13 pages

1981 In a study entitled A Comparison of the Crash Experience of Utility Vehicles, Pickup Trucks and Passenger Cars, researchers at the University of North Carolina's Highway Safety Research and IIHS analyze a large volume of rollover data from state and Federal (FARS) data bases and conclude that, among the vehicle groups, passenger cars had the lowest involvement in single vehicle rollover crashes and utility vehicles had the highest.

The track width and center of gravity of a vehicle are very important factors with respect to rollovers, the study states. Thus, it is not surprising that utility vehicles, which typically have higher centers of gravity than passenger cars and pickup trucks, are more likely to roll over. It may be that many drivers are aware of the different handling characteristics of these vehicles, and that they adjust their driving practices accordingly. However, the results of this study suggest that many other drivers are either not aware of the vehicle's handling characteristics or, if they are aware, do not or cannot adjust their driving practices to the extent necessary to avoid rollover. 53 pages

1981 A chronology of events relating to ìinvolvement of Jeep CJ-5 and other utility vehicles in rollover crashes is prepared by IIHS. The chronology and attachments detail a history of controversy over the issue of the CJ's rollover propensity. They summarize news coverage of the issue, including a segment on the IIHS tests by CBS 60 Minutes, and action by the Federal Trade Commission to compel American Motors to cease advertising risky uses of the CJ and to warn owners and buyers of the vehicle's handling hazards. 20 pages

1981 American Motors agrees, under pressure from the Federal Trade Commission, to cease and desist its deceptive acts or practices connected with the advertising and sale of Jeeps, and to warn owners of the hazards of on-road use of the vehicles. 3 pages

1982 The Center for Auto Safety and IIHS urge FTC to sharpen the warnings it is proposing to require for Jeep CJ owners, including a warning label on the vehicles' interiors. 2 pages

1982 An internal American Motors memorandum, disclosed subsequently in litigation, discusses proposed design objectives - future CJ upgrade or replacement, and under that heading describes improved on-road handling and stability as mandatory for product liability in the U.S. market. It goes on to enumerate the qualities that such a vehicle should have, and stresses that the Jeepís principal target market is young people. 3 pages

1982 NHTSA publishes a notice that it is considering requiring warning labels and warning information in owners manuals of utility vehicles, due to the apparent lack of public awareness about the proper handling and operation of multipurpose vehicles which have special features for off-road operation or, more simply, utility vehicles. It lists a number of vehicles with relatively short wheelbase, a narrow track, high ground clearance, a high center of gravity, stiff suspension system, and four-wheel drive,î including AMC Jeeps, Chevrolet Blazer, Ford Bronco, Plymouth Trail Duster, Dodge Ram Charger, VW Thing, Toyota Land Cruiser, and the GM Jimmy. It cites the University of Michigan On-Road Crash Experience study in support of the need for such warnings. 3 pages

1983 In reporting NHTSA's warning proposal, IIHS quotes a NHTSA letter to an attorney blaming the majority of Jeep crashes on speeding, reckless driving and alcohol. The Jeep CJ-5 appears to be less forgiving of incautious driving or unfavorable operating conditions than may be other vehicles, the NHTSA letter is quoted as saying. 2 pages

1983 NHTSA releases a year-long study Analysis of Fatal Rollover Accidents in Utility Vehicles, comparing fatal rollover accident rates per 100,000 registered vehicle-years for 11 utility vehicles. The rates range from a high of 52 for the Jeep CJ-5 to a low of three for the Jeep Wagoneer. The Toyota Land Cruiser at 47 and the Jeep CJ-7 at 35 exceed the vehicle with the next highest rate, the Chevrolet Blazer at 17, by more than double. 30 pages

1983 IIHS, reporting on the NHTSA study, presents charts comparing the single-vehicle fatal rollover involvement of a range of utility vehicles. 2 pages

1983 Citing the North Carolina study, Comparison of the Crash Experience, and NHTSAís own data, IIHS urges the agency to be selective in its choice of utility vehicles covered by the proposed warning label requirement. It warns that ìthe more common such labels become, the less effective they might become. 2 pages

1984 NHTSA issues its final rule requiring that manufacturers provide owners and operators of smaller utility vehicles with warning information, including specific language to be included in ownerís manuals and labels posted on vehicle interiors. If you make sharp turns or abrupt maneuvers, the vehicle may go out of control and crash. No reference is made to rollover on the label, nor does the label or manual information provide direction to drivers as to how sharp turns or abrupt maneuvers can be avoided in emergency situations. 9 pages

1984 New Jersey petitions NHTSA to go farther than a labeling requirement in regulating the safety of rollover-prone utility vehicles. In a letter to US DOT Secretary Elizabeth Dole, the director of the NJ Department of Law and Public Safety, Division of Motor Vehicles, urges among other things that performance and design standards should be formulated with an emphasis on roll stability and occupant safety. He cites the Stateís experiences with these vehicles, which are ìin agreement with the results of recent studies including the Michigan and North Carolina studies. Two pages

1984 The Highway Safety Research Center at the University of North Carolina publishes a second study, A Further Look at Utility Vehicle Rollovers, reaffirming the findings of its earlier report: In virtually every category of comparison the Jeep CJ-5 and the Jeep CJ-7 had the least favorable results of the various vehicles studied, generally by a factor of two or more. It says the Ford Bronco, Chevrolet Blazer, and other utility vehicles showed improving performance, but that intermediate and full-size cars showed by far the best results. The study provides tables and charts analyzing rollover data for utility vehicles against a wide range of variables, and concludes that utility vehicles with higher centers of gravity and narrower track widths than passenger cars and half-ton pickup trucks were more likely to be involved in rollover crashes. This finding was especially true for smaller utility vehicles. 75 pages

1986 Two researchers publish a paper, ìThe Role of Stability in Rollover-Initiated Motor Vehicle Crashes Under On-Road Driving Conditions, finding that vehicles with the lowest stability values the product of dividing the track width by twice the center of gravity (T/2h) had rollover-initiated fatal crash rates many times greater than those for the other make-models covered by the report. It identified both the CJs and pre-1978 Broncos, which had rates greater than 16 per 100,000 registered vehicles, compared with rates ranging from 0.6 to 4.7 for any other make-model, or a three to sixteen-fold difference. It also found strong correlations between stability factors and fatal crash involvement, and weak or non-existent correlations between other risk factors and miles driven, on one hand, and fatal crash involvement, on the other. 38 pages

1986 Rep. Timothy Wirth, chairman of the House Energy and Commerce Committee's Subcommittee on Telecommunications, Consumer Protection and Finance, petitions NHTSA to take steps to protect people who drive jeeps and jeep-type vehicles from getting killed in rollover crashes. Citing various studies that have shown the heightened involvement of small utility vehicles in fatal rollovers, he requests rulemaking to establish a federal motor vehicle safety performance standard, based on objective stability-factor criteria, to limit the rollover propensity of passenger automobiles, utility vehicles and pickup trucks, as well as a defect investigation covering makes and models of such vehicles whose propensity to roll over, based on their stability factors, exceeds that of the standard proposed above. Eight pages.

1986 An America Motors representative meets with NHTSA to discuss the Wirth petition. According to a NHTSA internal memorandum, he indicates that AMC would like to assist the agency in its evaluation of the petition. One page

1987 AMC writes to NHTSA urging that it not grant the Wirth petition because, among other things, the stability factor is not established as an objective and valid criterion for rulemaking or determination of defect as the petition asserts. It continues: Static ratios like T/2H have not been shown to be good predictors of dynamic rollover behavior... A criterion based on T/2h value is not supported by sound science. 23 pages

1987 NHTSAís associate administrator for plans and policies recommends in an internal memo that the Wirth petition be granted and that while the stability factor may not be the answer, it may play a role as part of some combination of factors that could be used as a future regulation or guideline. It would be ìparticularly troublesome for the agency to deny the petition in light of its own publications, including a report to Congress, documenting that the multipurpose vehicle fatality rate in rollover crashes is 196 percent above the average for light trucks and passenger cars combined, and that the higher center of gravity of these vehicles is a contributing factor. Two pages

1987 NHTSA's counsel states in an internal memo that ìdenial of the petition is difficult to justify if the agency focuses on the broader issue of utility vehicle rollover and the petition as seeking some agency action to mitigate that problem. The agency's own data confirm that rollover is a significantly greater hazard for utility vehicles, and that a requirement that utility vehicles have some minimum wheelbase could significantly reduce rollovers for these types of vehicles. While there is no simple solution, such as requiring some vehicle stability factor, to this problem, the agency would ìlook either uninformed or nitpicking by denying a petition on a subject that we agree appears to present a significant safety-related problem. 3 pages

1987 NHTSA's associate administrator for research and development, in a detailed and strongly-worded internal memorandum, recommends that the Wirth petition be granted. In support, the memo states that previous research conducted by NHTSA and others concerning the mechanics of vehicle rollover has shown that the vehicleís rollover resistance is dependent to the first order on the ratio of the half-track to center of gravity height (rollover stability factor) for both tripped and untripped rollover. 32 pages

1987 Within NHTSA, a draft paper entitled Analysis of the Relationship Between Vehicle Rollover and Stability and Rollover Risk, Using NHTSA CARDfile Accident Database, scheduled for presentation as a Society of Automotive Engineers meeting later the same month, is circulated for comment: This paper may have a bearing on Rulemaking's action regarding the petition submitted by Senator Timothy Wirth. The paper concludes: Statistical confirmation of the important relationship between vehicle rollover stability, as defined by the ratio of half track width to center of gravity height, and rollover risk, has been established using data extracted from the automated police accident reports of three states. Tests for the effect of a variety of factors on rollover rate, including driver traits, and environmental factors, further substantiate the tendency for this type of crash to be associated with vehicles possessing a low rollover stability index. 48 pages

1987 Noting that Analysis of the Relationship and an internal NHTSA memorandum take conflicting positions on the Wirth petition and NHTSA's possible course of action toward addressing the utility vehicle rollover problem, the associate administrator for research and development, in an internal memorandum, urges that Analysis be modified to more objectively discuss the rollover issue by recognizing that, according to the memo, track width, wheelbase, c.g. height and size all were found to correlate with rollover risk. Three pages.

1987 NHTSA's general counsel writes in a note: I strongly recommend that this paper [ìAnalysis of the Relationship] not be presented at the SAE meeting. The very first sentence of the abstract states that the statistical confirmation of the relationship between rollover stability and rollover risk has been established. Such a statement is the basis explicitly set forth in the Wirth petition for the requested rulemaking and defect investigation it would establish an unwise policy and management course to publish this paper, addressing the key point of the Wirth petition, before we have officially responded to the petition. One page

1987 An internal memorandum headed, Staff Recommendation to Grant Congressman Timothy Wirth Petition, sums up the conclusions of NHTSA's senior policy and operational staff and requests that the Office of Chief Counsel prepare a Federal Register notice to grant the subject petition. That notice should stress that the agency does not support the exclusive use of the stability factor as the only appropriate or reasonable way to address the problem and should indicate that the agency will develop a work plan to define the efforts that the agency intends to undertake in response to the subject petition. Five pages

1987 The agency's administrator overrules the staff recommendation to grant the Wirth Petition and states that she will deny it, based on the fact that there is little likelihood of any rulemaking on this subject in the foreseeable future. The approach proposed by the petitioner, by itself, is not a reasonable or practicable method upon which to base a regulation. The amount of research that would be necessary to adequately understand the issues involved and to develop a rulemaking approach is likely be to be extensive and lengthy. One page.

1987 A NHTSA senior researcher, Kennerly Digges, delivers a paper entitled, Light Truck Safety Research in NHTSA. Data and figures in the paper show the large disparity between human harm caused by rollovers of light truck and van vehicles (48%) and rollovers of passenger cars (20%). He stresses the large contribution of ejection to this harm. Nine pages.

1987 A consumer information advisory issued by NHTSA entitled, Utility Vehicles, repeats the information required by the agency in utility vehicle owners manuals and on interior labels. Do you drive a Samurai, Jeep, Bronco, Pathfinder, or Blazer? the advisory asks. Later versions of the advisory omit specific names of SUVs and other utility vehicles. Two pages

1988 NHTSA's Office of Crash Avoidance Research issues a report, Statistical Estimation of Rollover Risk, examining a number of variables from the standpoint of their possible importance in rollover propensity determination. It concludes: The stability factor is by far the most important variable among those we examined for predicting rollover. The results of previous studies, including the Analysis of the Relationship, have been confirmed and strengthened by these results. Those studies were strictly at the make/model level. We have, in addition, shown that stability factor is the single most important factor at the accident level and the strength of its effect is almost unaffected by nonvehicle factors. 70 pages

1988 A study sponsored by the Motor Vehicle Manufacturers Association and undertaken by Franklin Research Center reaffirms that light trucks had substantially higher rollover and ejection rates than cars and that utility vehicles exhibit clearly the highest rollover tendencies. 130 pages

1988 IIHS criticizes NHTSA for denying the Wirth petition. In a statement it says: Whether or not the stability factor predicts the likelihood of involvement in single-vehicle crashes is irrelevant. What should be at issue for rulemaking is whether or not a rule would reduce the likelihood that crashes become rollovers, which have serious consequences. Clearly, preventing the sale of vehicles with poor stability factors would do that. It adds that ìdesign solutions are simple and inexpensive for the most dangerous utility vehicles. Smaller diameter tires would reduce the height of the center of gravity, and wheels also could be offset to widen the track, as has been done with the redesigned Jeep Wrangler. Two pages

1988 The current chairman of the House Subcommittee on Transportation, Tourism and Hazardous Materials questions the NHTSA administrator for denying the Wirth petition and for refusing to respond to press inquiries over whether she vetoed her staffís recommendations to grant the petition. Rep. Tom Luken, joined by Commerce Committee Chairman John Dingell, in a letter to Diane Steed , the administrator, asks: Was such a recommendation made? Did you veto it? If so, why? Please provide us with a copy of all internal letters, notes, memoranda, studies, etc. in NHTSA and department files concerning the issue. We intend to find out why NHTSA is not doing more than simply requiring a warning label and issuing a pamphlet. One page

1990 Two years after its denial of the Wirth petition, NHTSA publishes Safety Programs for Light Trucks and Sport Utility Vehicles, summarizing its on-going activities concerned with crash avoidance and crashworthiness of utility vehicles, including establishing ìa new data base of rollover accident characteristics and examining the dynamic stability and rollover propensity of such vehicles, including through the use of sophisticated simulationî techniques. Results should be available in mid-1991. 66 pages

1990 In Engineering Parameters Related to Rollover Frequency, two researchers examine vehicle parameters affecting stability and conclude that reducing the track width to center of gravity height ratio of trucks to that of passenger cars could reduce rollover frequency by as much as 60 percent. 24 pages

1990 Three consumer advocacy groups petition NHTSA to undertake defect investigations into the undue, unnecessary and defective propensity of Jeep CJ-5 and CJ-7 vehicles to roll over under foreseeable handling conditions. They also request that the agency investigate whether corporations involved with the CJ's manufacture and sale have violated the law with respect to manufacturers obligations to disclose knowledge of safety defects in motor vehicles and to take specified notification and recall action based on such knowledge. 18 pages

1990 NHTSA denies the petition by the three consumer advocacy groups. We have reviewed updated information supplied by Chrysler Corporation [successor to American Motors as Jeep's manufacturer] in response to our current inquiry. This additional data does not suggest the existence of a defect. NHTSA adds that its denial ìshould not be read as a determination by this agency that CJs are safe or that drivers of CJs need not be concerned about the possibility of rollover. Four pages

1991 In a technical assessment paper, NHTSA describes in detail its work to find bases for measuring rollover propensity other than the Static Stability Factor (SSF). Although it reaches no final conclusions and calls for further research, the paper, Relationship Between Rollover and Vehicle Factors, appears to find that the SSF and the leading technique for dynamic measurement of rollover propensity provide equivalent results. The side pull ratio and static stability factor are approximately equal as vehicle metrics static stability factor had a better correlation with the accident data than did the side pull ratio. 156 pages

1992 IIHS publishes a study, Fatal Rollover Rates of Small Utility Vehicles and Pickups, finding that during 1986-1990, occupant death rates in rollovers of small utility vehicles of the 1985-1989 model years exceeded those of other vehicles, with small pickups the next worse. ìMore than 80 percent of the single-vehicle crashes in small utility vehicles involved rollovers. The Ford Bronco II, especially the two-wheel drive version of this utility vehicle, had the highest rollover rate, followed by the four-wheel drive Nissan short-bed pickup truck. It adds: ...in this study several small four-wheel pickups were found to have higher occupant death rates in rollover crashes than all utility vehicles other than the Ford Bronco II. These pickups tend to be those with high centers of gravity and narrow track width. Twelve pages

1992 NHTSA publishes a Planning Document for Rollover Prevention and Injury Mitigation, in which it describes future rulemaking plans that would ìdecrease the number and severity of rollover crashes. It notes that after denying the Wirth petition, NHTSA granted a petition from Consumers Union to establish ìa minimum stability standard to protect against unreasonable risk of rollover, and in January 1992 issued an Advance Notice of Proposed Rulemaking looking to eventual adoption of a rollover standard, as required by the NHTSA Authorizations Act of 1991. Rollover crashes are complicated, the document says, and eliminating them is probably impossible.. [A] major reduction in occurrence, in all likelihood, cannot be attained with a single rulemaking. Thus, an agency-wide effort focused at reduction of various kinds of rollover crashes and casualties is needed. Such an effort would involve most of NHTSA's program offices. As for setting regulatory vehicle performance parameters to limit rollover, the static stability factor and another dynamic test approach, the tilt table ratio, were found to be the most highly correlated to the rate of rollovers per single vehicle accidents (TO/SVA). The document states that a regulatory decision on stability will be made in winter 1992-93 . As of October, 2005, no decision had been published by NHTSA. 14 pages

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