Defective Automobile Seats
Posted in on January 30, 2014
By: Mark P. Robinson, Jr. and Kevin F. Calcagnie
INTRODUCTION
As a result of wide-spread media exposure there it is a significant degree of public awareness concerning motor vehicle crashworthiness and safety, and certain potential design defects such as those in fuel systems, airbags and seatbelts. However, relatively scant attention has been paid to a wide-spread design flaw present in literally millions of automobiles on the road today, which poses a substantial threat to life and limb seats which fail in low speed to moderate rear-impact collisions. As a direct result of weak and defective designs of seats and their components, such as seatbacks, recliner mechanisms and seat tracks, thousands of otherwise preventable injuries occur each year in rear-impact collisions, and mfany involve fatalities as well as Catastrophic Injuries, including brain damage and quadriplegia. Much like other notorious automotive design defects, the problems with seats stem from an inadequate Federal Motor Vehicle Safety Standard, caused in part by the resistence of some manufacturers to reasonable and safer proposed standards. Likewise, the sorry history of seatback design evolution shows an industry ignoring its own engineers by rejecting inexpensive safe alternative designs that have been available for decades.
THE FUNCTION OF A CAR SEAT THE SEATBACK AS AN OCCUPANT RESTRAINT SYSTEM
It is a fundamental principle of automotive safety that vehicles should be designed in such a manner as to reduce or eliminate, as much as reasonably practical, risks of injury associated with foreseeable collisions and impacts. It is also a recognized principle of product liability law that although a collision may not be the normal or intended use of a motor vehicle, vehicle manufacturers must take accidents into consideration as reasonably foreseeable occurrences involving their products.[1]
“A motor vehicle manufacturer is required to foresee that as an incident of normal operation in the environment in which his product will be used accidents will occur, including high-speed collisions between vehicles. Because of this possibility he is required to design his vehicle to minimize unreasonable risk of injury and death…Stated more generally, the law now requires the manufacturer to foresee some degree of misuse and abuse of his product, either by the user or by third parties, and to take reasonable precautions to minimize the harm that may result from misuse and abuse. The manufacturer must evaluate the crashworthiness of his product and take such steps as may be reasonable and practical to forestall particular crash injuries and mitigate the seriousness of others.”[2]
While the structure of the vehicle itself is a significant factor in protecting passengers from collision injuries, it has been shown that the crash safety of a motorist is more dependent upon the use of adequate occupant restraint devices than the size of the vehicle itself.[3] When it comes to minimizing or eliminating the risk of injury, the automobile seat plays a significant role in that regard. Much like the seatbelt system prevents an occupant from moving forward in a frontal collision, the seat should perform the same function in a rear-impact collision, in preventing the occupant from excessive motion relative to the vehicle interior, and preventing the occupant from striking the interior of the vehicle or being ejected. The safety contribution of the seat is essentially of occupant restraint:
“A fundamental parameter of safety is ‘restraint compliance’, the change in restraint geometry induced by occupant inertial forces. A seat should be designed to transmit these forces to the vehicle, and then moderate them so that occupant displacement and acceleration avoid levels causing physiological trauma. In short a seat should minimize injury to its occupant in the event of a collision…”[4]
A vehicle’s seat controls guidance of occupant kinematics, making it the decisive element in the effectiveness in a vehicles overall protective system.[5] Because they are of the primary occupant restraint system for rear impacts, automobile seats have been called the most important safety feature that may be provided for motorists and “the most important single lifesaving device available.[6]
Despite their significance as a safety feature, most automobile seats present a significant safety hazard in a rear-impact collision. Just like other defective automotive design features, manufacturers are permitted to produce defective seats as a result of a weak and ineffective Federal Motor Vehicle Safety Standard.
FEDERAL MOTOR VEHICLE SAFETY STANDARD 207
Prior to the 1960’s, there were no nationwide standards controlling the design performance of automotive seats, and seat designs remained essentially unchanged for decades. In the ’20s fore-aft adjustments, as well as forward folding backrests were first introduced. By the mid-1930’s, the basic design of seats, tracks and runners closely resembled vehicles of the ’60s. In 1963 the Society of Automotive Engineers promulgated minimum standards for seat performance. The standard proposed two tests, one evaluated retention capability of adjusters and anchorages, and the other set a minimum standard of 4250 in.-lb for back rest strength.[7] The SAE recommendations were adopted by the General Services Administration into the federal purchasing requirements for the 1967 model year.[8]
The Motor Vehicle Safety Act of 1966 required that initial standards be promulgated based upon existing safety standards, and on December 3, 1966, the National Traffic Safety Administration, precursor to the National Highway Traffic Safety Administration (NHTSA) issued a notice of proposed rulemaking regarding the initial Federal Motor Vehicle Safety Standard (FMVSS) for seat anchorage — FMVSS 207.[9] The notice proposed a standard to establish requirements for seats, their attachment assemblies, and their installation “to prevent failure and dislocation by forces acting on the seat as a result of vehicle impact.”
The proposed standard required application of a load equal to thirty times the weight of the entire seat in both forward and rearward longitudinal directions, through either dynamic or static testing techniques. It also proposed that static testing of the seats be performed in accordance with SAE J879a. The Automobile Manufacturer’s Association, Inc., whose members included Ford Motor Company, American Motors Corporation, General Motors Corporation, Mack Trucks, Kaiser Jeep Corporation, International Harvester and Chrysler, objected to any proposed design requirements that were considerably different from the existing SAE standard. Additionally, the AMA proposed substituting the language “reduce the likelihood of failure and dislocation” in place of “to prevent failure and dislocation.”[10]
On December 30, 1966, General Motors submitted a critique of the proposed FMVSS 207, arguing that increasing the load requirement to thirty times the weight of the entire seat would not reduce the injury potential for the front seat occupant, and that the resulting increase in seatback stiffness may well eliminate the energy absorption advantages of current seatbacks, and increase the injury potential to rear seat occupants.[11]
On February 3, 1967, the NHTSA issued a final rule requiring that folding forward backrest locks of seats withstand a load of only twenty times the weight of the entire seat (20g) in a longitudinal direction. The standard also requires that seatbacks sustain a rearward static moment equal to 3300 in.-lb applied to the upper crossmember in a rearward longitudinal direction.[12] Two years later the NHTSA extended the requirements of FMVSS 207 to extend to multipurpose passenger vehicles, trucks and buses.[13] In 1974 the Council of European Communities adopted a standard essentially the same as FMVSS 207.
SEAT FAILURE
Although 3300 in.-lb may sound like a significant standard, FMVSS 207, has been widely criticized in the automotive safety community since its inception. It does not represent an improvement over earlier designs, and in fact, production seats from the 40’s and 50’s have been found to substantially exceed this standard.[14] Aside from its low threshold force requirement, FMVSS 207 is static rather than dynamic, and it does not simulate what occurs to the seat and the forces imparted to occupants in real world crashes. Ironically, the rear barrier impact crash testing required by FMVSS 301, the standard for fuel system integrity, demonstrates the inadequacy of FMVSS 207. During 301 rear impact tests at 30 mph, almost all bucket seatbacks and split bench seatbacks fail and strike the rear seats.[15] Some manufacturers readily concede that their seatbacks are not designed to withstand dynamic rear sled or moving barrier tests at 30 or 35 mph, such as those encountered in NHTSA 30 mph compliance and NCAP 35 mph tests.[16]
While most auto manufacturers have internal standards which exceed FMVSS 207 these internal standards are still insufficient to prevent seat failure in a reasonably foreseeable rear- impact collision. As a result, seats and their components suffer a variety of failure modes in rear- impact collisions including breakage of seat adjusters, breakage of folding seatback locks and supports, or separation of the anchorage from the vehicle.[17]
Decades ago automotive design safety experts recognized the potential for injuries as a result of seat failure:
“High-speed impacts may force the front seat passenger up the plane of the back-rest to whiplash him or break the seatback, releasing him to the rear seat area or even out the rear door, notwithstanding the use of a lap belt; neither of these extremes represent acceptable or satisfactory solutions to a serious and very frequently occurring type of accident.
“Interoccupant injuries may occur when the front seatback yields excessively and allows the occupant to be flailed rearward to strike the rear passenger during rearend collisions…”[18]
Research demonstrated that when rear-impact collisions deflect seatbacks rearward, occupants are allowed to ramp up over the seatback and head restraints, exposing them to neck injuries.[19] In upset or rollover conditions there can be excessive passenger flailing and impacting about the vehicle interior, even when the occupants are wearing seatbelts, due to the seatback and seat being readily displacible.[20] Although seatback strengths varied from 4000 to 17,000 in.-lb, safety experts in 1976 concluded that no seats provided adequate protection under more than moderate collision induced forces.[21] In 1970 one Ford Motor Company engineer concluded:
“Seatback strength is quite low in most American vehicles, withstanding approximately a 3200 in.-lb bending moment before failing rearward. In a rearend collision, this rearward bending of the seatback might be construed to allow the occupant to ride up the seatback, and thereby compromise the effectiveness of the head restraint. However, the actual highway accident evidence strongly indicates that this flexing of this seat very effectively attenuates whiplash injury.”[22]
In full-scale collision experiments performed to evaluate crash performance, the danger of seatback failure was clearly demonstrated with anthropormorphic dummies:
“The inertial loading of the driver’s torso against the backrest caused it to fail; the torso followed the seatback rearward as it slid 8-10 inches up the plane of the backrest and the head of the dummy continued rearward in a normal posture relative to the driver’s shoulder-neck alignment until the backrest struck the knees of the rear passenger. The driver’s head received a severe impact of 120 g’s at 155 ms. as it struck the rear passenger’s chest. He thereafter rebounded to a rest position partially lying on his permanently deformed seatback.”[23]
Another study concluded:
“The magnitude of accelerations developed in severe collisions can produce motions that result in the head of the occupant striking the roof of the passenger compartment due to a ramping motion up the seatback or, in the case of inadequate seatback strength, rearward deflection of the seatback, and eject the unrestrained occupant out of the seat with possible serious impact with the rear window area of the vehicle…”[24]
Researchers also opined that even occupants using their seatbelts were at risk for injury due to seatback failure and deflection. Although designed fundamentally for frontal accidents, seatbelts assist in rear accidents to prevent occupants from sliding up the seatback.[25] If seatback failure occurs, the use of the occupant’s restraint system may not prevent the occupant from being ejected from the vehicle.[26] Additionally, if the backrest is in a reclined position “submarining”, can occur, shifting the belt upward across the viscera if the occupants body moves forward.[27]. In one study of 23 rear impact accidents involving front seat collapse, it was found that a majority of restrained front seat occupants were either partially or totally ejected from the seat systems during impact, even at changes of velocity as low as 18 mph or less.[28]
The potential problems of the failure of automotive seat systems are best summarized by Dr. Kenneth Saczalski, an expert on automotive seat safety:
- “Loss of vehicle control by a driver when the seatback collapses rearward in an uncontrolled manner during a rear impact;
- “Reduced effectiveness of the restraint system when the collapsed seatback allows the front seat occupant to rotate and slide rearward from under the lap belt during a rear impact, thus enabling potential injurious contact with rear seat objects and passengers;
- “Ejection of occupants who have slid out from beneath their lap and shoulder harness system…
- “Injury to rear seat passengers who are likely to be struck by the violent rearward motion of the front seat occupant collapsing into their rear seat passenger area…
- “Reduction or loss of egress capabilities of rear seat passengers whose bodies are likely to be trapped under the plastically deformed and collapsed front seatbacks…
- “Injury to fully restrained front seat passengers during a frontal impact when the seatback easily collapses from the rear loading of a lap belted or unrestrained rear seat passenger (or heavy object)…”[29]
The consequences of seat failures are serious and sometimes fatal injuries, due to impact in the interior of the vehicle or ejection from the vehicle and contact outside.[30] In some cases occupants in the rear seat are killed as a result of seats in front of them, loaded with a passenger, collapsing onto them.[31] It has been estimated by the National Highway Traffic Safety Administration that in 1990 alone 1,100 people died and 1,600 more sustained serious injuries because their seats collapsed rearward in rear-impact collisions.[32]
PROPOSED SOLUTIONS AND RECOMMENDATIONS
The same automotive engineers who identified the safety hazards of conventional seat designs also identified exactly what would be necessary for the industry to eliminate the dangers of seat failure. Consistent among the recommendations was that seatbacks be exceptionally rigid with head support structures sufficient to restrain the motorist in a normal seated posture throughout a collision,[33] and that the seat remain intact and anchored in position, so that the occupant will be restrained and retained in the seat throughout the collision energy transfer, thereby providing maximum protection from rear-impact crash injuries.[34]
Almost three decades ago it was recommended that seatback strength should be increased to 100,000 in.-lb, and that seatback deflection should be limited to ten degrees rearward under 30 g collision conditions.[35] Another recommendation called for a seat strong enough to protect against 40 g loads.[36] In 1970, a Ford Motor Company engineer predicted:
“Future Trends – As measures are developed to provide better restraint of the head, seatback strength will probably be increased to better retain the occupant in his seat. The intent, in this instance, would be to prevent his contact with rear seat occupants. The degree of increase and resistence to rearward bending may be anywhere from two or three times, to more than ten times the current level.”[37]
Recommendations such as these have been based upon accident data, as well as full-scale crash testing, and research going back 50 years which shows that human tolerance to rear-impact collisions is as much as 40 g’s. However, occupants in contemporary automobiles are unnecessarily injured because of weak and ineffective seats at exposures of only a fraction of this tolerance level:[38]
“A typical FMVSS 301 test, which constitutes a 48 kph (30 mph) moving barrier, induces acceleration levels to the occupant compartment of approximately 12 g. Based on these results and the authors’ many observations, it is difficult to project that an occupant compartment could even see a 30 g collision and still maintain a survivable volume with most automobiles…
“Based on the proper use of human tolerance data one can rationally conclude that seats should remain rigid during most rearend exposures seen in automobile collisions, since the acceleration level of human tolerance is rarely seen. Hazards resulting from yield and collapse of the front seatback are devastating. There is obviously no engineering or human tolerance basis for such inadequate designs…
“A minimal amount of strategically applied metal, along with proper seat padding and contour, would eliminate the unnecessary hazards that often result in fatalities or serious injuries.”[39]
ALTERNATIVE DESIGNS
The existence of practical, safer alternative seat designs, which are both economically and mechanically feasible, is evidence that many of the injuries and fatalities associated with seat failures have been and are unnecessary and preventable. In 1968 automotive safety experts demonstrated through crash testing that a 28 inch high rigid seatback which controlled deflection to 10 degrees, would protect most passengers against sustaining any injury in rear-impact collisions up to 55 mph.[40] In 1969 a Ford Motor Company study determined that by 1973 improvements could be made to front seats in several vehicles in order to withstand 30 mph barrier impacts. The paper concluded that modifications, which included strengthened tracks, attachments and latches, would cost approximately fifty cents per vehicle.[41]
In 1974 Ford developed and tested a stiffened seat with a high and rigid head restraint, which withstand a moving barrier impact of 48 kph, allowing only 20 degrees rearward deflection.[42] More recently, in 1989, Dr. Saczalski showed that a 56,000 in.-lb requirement could be met with state-of-the-art materials and manufacturing techniques (with only a modest weight increase) while still enabling seatback and seat cushion adjustments.[43]
Moreover, stronger, safer seats, which will withstand moderate rear-impact impacts, are not confined to test facilities and drawing boards. In 1992, a Mercedes-Benz advertisement proclaimed:
“On February 16, a national T.V. audience learned one major difference between every Mercedes and many average cars: Front seats designed to withstand the energy of rear impact…In a 30 mph car to car impact, the backrest’s ability to absorb energy and resist collapsing is important. In a Mercedes-Benz seat, the backrest hinge point is designed to resist very high ‘bending moments’…The backrest frame’s sturdy formed-steel uprights and crossmembers are designed to resist bending rearward, and twisting, in a wide range of impacts…The seat is securely mounted on tracks bolted to reinforced anchor points in the floor.”[44]
According to the manufacturer, all Mercedes-Benz seats “are designed to perform without ‘failure’, i.e., breakage and collapse, in a Standard 301 rear-impact crash test.”[45]
PROPOSED AMENDMENTS
Along with the recognition in the engineering community that the requirements of FMVSS 207 are so low and so far removed from real-world crashes as to be irrelevant, there have been calls to amend the standard to a level designed to approximate forces encountered in foreseeable rear-impact collisions. In 1974 the NHTSA proposed crash testing requirements similar to FMVSS 301, which combined requirements for seat performance and head restraints.[46] However, in part because of auto industry opposition, the proposed regulation was abandoned in 1979.[47] On April 18, 1989, Dr. Kenneth Saczalski petitioned the NHTSA to reexamine the general performance requirements of FMVSS 207, and suggested that the standard should require not just twenty times the weight of the seatback, but twenty times the weight of the occupant.[48] In a subsequent letter Dr. Saczalski pointed out the hazards of seatback collapses and requested that the NHTSA implement a limit on the amount of seatback deflection to no more than 40 degrees from the vertical, and also implement improved torque requirements of at least 50,000 in.-lb.[49]
Also in 1989, another auto safety expert, Alan Cantor petitioned NHTSA to amend FMVSS 207 to prohibit an occupant from ramping up a seatback during a collision. The petitions were granted on October 4, 1989 and February 28, 1990, respectively.[50] Ever resistant to change, some manufacturers responded in predictable fashion. Despite an absence of any data or engineering rationale, and despite internal testing showing just the opposite, General Motors and Ford argued against strengthening seats. According to General Motors:
“Increased seat stiffness is unlikely to reduce occupant injury, and could result in greater occupant injury exposure. While seatbacks that have been significantly deformed as a result of occupant loading in rear impacts are in evidence in field data examined by GM, this yielding is associated with more severe impacts. Only rarely is injury associated with the yielding.…It should be further noted that implementation of proposals to stiffen vehicle seats to the extent proposed would significantly increase cost and mass…”[51]
According to Ford Motor Company:
“Ford believes that the energy absorption that results from seatback deformation during rear impacts is generally beneficial in mitigating potential injuries,…Current Ford seat design practices to optimize seat design for front and rear impact, assuming that all vehicle occupants are restrained…Some seatback movement is considered desirable to reduce risks of injuries to restrained rear occupants. In addition, some seat deformation is believed to reduce injuries to restrained front seat occupants in rear impacts…We believe that a seatback designed to withstand a static moment of 56,000 in.-lb would be overly stiff for any conceivable accident situation…Further, there is no consensus on the criteria for neck injury in the biomechanics community.…”[52]
In another letter concerning seatback performance Ford opined:
“Although further research on rear impacts is desirable, Ford encourages the agency to concentrate its efforts on issues and areas that are more likely to provide tangible improvements in automotive safety, and to allow vehicle manufacturers to also concentrate their efforts on more promising safety initiatives. Ford believes there is no safety need to adopt a dynamic test of seat performance in rear impacts, and opposes the adoption of a complicated test procedure such as moving barrier impact with instrumented dummies…”[53]
The claim that seat deformation in a rear-impact collision is actually beneficial is analogous to recommending failure of a seatbelt during a frontal impact.[54] Moreover, the manufacturers’ arguments in opposition to improved seatback performance requirements are contradicted by their past studies as well as current research. For example, a General Motors patent for a “high retention seatback” provides:
“If the rearend collision is severe enough, the load imposed against the backrest unit becomes severe and tends to cause the seatback rest unit to be deflected rearwardly from its normal upright position by twisting or rotating about its pivotal connection with the seat cushion unit and/or due to bending of the backrest frame in a rearward direction…At angles greater than a substantial angle from the vertical the occupant tends to ramp rearwardly and off the seat assembly, especially if the occupant is not wearing a seatbelt…Accordingly it is a broad object of the present invention to provide a new and improved vehicle seat assembly…which includes a seatback retention means which prevents or limits rearward rotation of the seatback rest unit about its connection with the seat cushion unit.”[55]
Even owner’s manuals warn of the risk of a reclined seat. According to the 1988 Mustang/Thunderbird/Cougar/Grand Marquis Owner’s Manual:
“Warning: To minimize the risk of a personal injury in the event of a collision or a sudden stop, both the driver’s and the passenger’s reclining seatbacks must always be in a fairly upright position while the vehicle is in motion. The protection provided by the seat and shoulder belts is significantly reduced when the seatback is not in the upright position.”
Although the industry generally opposed any modification of FMVSS 207, in 1992 Mercedes-Benz suggested a substantial increase in the rear impact strength requirements, and a dynamic test similar to FMVSS 301:
“We recommend that you replace the static test in Standard 207 with the Standard 301 rear impact crash test using belted dummies and performance criteria such as HIC. The dynamic test would more accurately replicate real world conditions; test both the seat structure and its anchorages; and ensure that any interaction with the seat, seatbelt, head restraint, and other parts of the vehicle do not result in undesirable occupant loading…”[56]
In 1998, Volvo published a study regarding a new seat concept designed for reducing neck injuries in rear-impact impacts, utilizing seats that are “several times stronger than required by existing legal requirements for backrest strength”:
“The new recliner matches the strength of the existing backrest, meaning that the high-speed crash performance has not been compromised by the new design. Thus, there is no increased risk, neither for the occupant of a front seat nor for adult or child occupants of a rear seat.”[57]
CONCLUSION
Until reasonably safe collision performance requirements become a part of FMVSS 207, some auto manufacturers will continue to resist efforts to eliminate the defects in the seats of most vehicles on the road today. In the meantime, thousands of people will suffer catastrophic and fatal injuries which are preventable and avoidable. It is hoped that industry pressure from other competitors and automotive safety experts, as well as product liability litigation, will force these manufacturers to eliminate their defective designs, in order to bring about the necessary degree of safety which government standards have failed to achieve.
[1] Passwaters v. General Motors Corporation, 452 F.2d 1270, 1276 (8th Cir. 1972); Larsen v. General Motors Corporation, 391 F.2d 495, 501-503 (8th Cir. 1968)
[2] Self v. General Motors, (1972) 42 Cal.App.3d 1, 7, 116 Cal.Rptr. 575.
[3] D. Severy, et al., Smaller Vehicle versus Larger Vehicle Collisions, Institute of Transportation and Traffic Engineering, U.C.L.A. (1971) SAE 710861
[4] D. M. Severy et al., Designing Safety Seats, Automotive Engineering, Volume 84, No. 10 (October 1976)
[5] D. Adomeit, Seat Design – A Significant Factor for Safety Belt Effectiveness, Institute of Automotive Engineering, Technical University Berlin (1979) SAE 791004
[6] D. Severy, et al., Safer Seat Designs, (1969) SAE 690812
[7] Society of Automotive Engineers Recommended Practice J879a, November 1963
[8] GSA Standard No. 515, 31 FR 9633 (July 5, 1966)
[9] 31 FR 15212; Docket 3-1, December 3, 1966
[10] Comments of Automobile Manufacturers’ Association, Inc. on Proposed Initial Federal Motor Vehicle Safety Standards, January 2, 1967
[11] Comments of General Motors Corporation on Proposed Initial Federal Motor Vehicle Standards, December 30, 1966
[12] 32 FR 2408, February 3, 1967
[13] 34 FR 14661, September 20, 1969
[14] Severy, Blaisdell and Kerkhoff, Automotive Seat Designs and Collision Performance, (1976) SAE 760810
[15] TES Limited, Accidents Involving Seatback Failures, prepared for Transport Canada (December 1989) Report No. C1322/2
[16] Ford Motor Company internal document, Seatback Strength Issues, February 29, 1992
[17] 57 FR 54962 et seq., November 23, 1992
[18] D. Severy, et al., Collision Performance LM Safety Car Institute of Transportation and Traffic Engineering, University of California (1967) SAE 670458
[19] G. Carlsson, et al., Neck Injuries in Rearend Collisions, American Association for Automotive Medicine Quarterly Journal, July 1985
[20] D. Severy, et al., Safer Seat Designs (1969) SAE 690812
[21] D. M. Severy and J. M. Kerkhoff, Designing Safer Seats, Automotive Engineering, Volume 84, No. 10 (October 1976)
[22] R. Daniel, Automotive Safety Research Office Ford Motor Company, State-of-the-Art Vehicle Interior Safety Constraint Systems, (1970) SAE 700423
[23] D. Severy, et al., Smaller Vehicle versus Larger Vehicle Collisions, Institute of Transportation Traffic Engineering, U.C.L.A. (1971) SAE 710861
[24] J. W. Melvin and J. H. McElhaney, Occupant Protection in Rear-End Collisions
[25] D. Burland, Ford Motor Company, Occupant Protection in Rear Impact, June 4, 1974, US DOT NHTSA NO. R40003
[26] TES Limited, Accidents Involving Seatback Failures, prepared for Transport Canada (December 1989) Report No. C1322/2
[27] D. M. Severy, et al., Designing Safer Seats, Automotive Engineering, Volume 84, No. 10 (1976)
[28] K. Saczalski, et al., Field Accident Evaluations and Experimental Study of Seatback Performance Relative to Rear-Impact Occupant Protection, (1993) SAE 930346
[29] Letter from D. Kenneth Saczalski, Environmental Research and Safety Technologies to National Highway Safety Administration Regarding Docket No. 89-20, Notice 1 Seating Systems (November 29, 1989)
[30] K. Saczalski, et al., Field Accident Evaluations and Experimental Study of Seatback Performance Relative to Rear-Impact Occupant Protection (1993) SAE 930346; R.W. Thompson, et al., Dynamic Requirements of Automobile Seatbacks, (1993) SAE 930349; TES Limited, Accidents Involving Seatback Failures, prepared for Transport Canada (December 1989) Report No. C1322/2
[31] V. Gupta, et al., Improved Occupant Protection Through Advanced Seat Design, (1996) National Highway Traffic Safety Administration Paper No. 96-S1-O-08
[32] Discover, Automotive and Transportation, June 1993
[33] D. Severy, et al., Vehicle Design for Passenger Protection from High-Speed Rear-End Collisions, Institute of Transportation and Traffic Engineering, University of California, Los Angeles (1968) SAE 680774
[34] ARCCA Incorporated, Seat-Back Yielding and Collapse: A Danger to Occupants During Real-World Collisions, American Society of Mechanical Engineers 1993 Bioengineering Conference.
[35] D. Severy, et al., Safer Seat Designs (1969) SAE 690812
[36] R. G. Snyder, A Survey of Automotive Occupant Restraint Systems: Where We’ve Been, Where We Are and Our Current Problems, (1969) SAE 690243
[37] R. Daniel, Automotive Safety Research Office Ford Motor Company, State-of-the-Art Vehicle Interior Safety Constraint Systems, (1970) SAE 700423
[38] W. Muzzy and A. Cantor, et al., Seat-Back Yielding and Collapse: A Danger to Occupants During Real-World Collisions, ARCCA Incorporated (1993)
[39] W. Muzzy and A. Cantor, et al., Seat-Back Yielding and Collapse: A Danger to Occupants During Real-World Collisions, ARCCA Incorporated (1993)
[40] D. Severy, et al., Vehicle Design for Passenger Protection from High-Speed Rear-End Collisions, Institute of Transportation and Traffic Engineering, U.C.L.A. (1968) SAE 680774; D. Severy, et al., Safer Seat Designs, (1969) SAE 690812
[41] 1973 Passenger Car Safety Program, Ford Internal Document, May 19, 1969
[42] D. Burland, Ford Motor Company, Ltd., Occupant Protection in Rear Impact, Fifth International Technical Conference on Experimental Safety Vehicles, US DOT NHTSA Document No. R40003
[43] Letter to Diane Steed, Administrator, National Traffic Safety Administration from Dr. Kenneth Saczalski, April 18, 1989
[44] Mercedes-Benz advertisement, Los Angeles Times, February 23, 1992
[45] Letter from Thomas Baloga, Manager Safety Engineering, Mercedes-Benz of North America, Inc., to Barry Felrice, Associated Administrator for Rulemaking, NHTSA, March 17, 1992
[46] 39 FR 10268, March 19, 1974
[47] “Five-Year Plan for Motor Vehicle Safety and Fuel Economy Rulemaking Calendar Years 1980-1984” NHTSA April 20, 1979
[48] Letter to Diane Steed, Administrator, National Traffic Safety Administration from Dr. Kenneth Saczalski, April 18, 1989
[49] Letter from Dr. Kenneth Saczalski, Environmental Research and Safety Technologist to National Highway Safety Administration Regarding Docket No. 89-20, Notice 1 Seating Systems (November 29, 1989)
[50] PRM-207-001, April 18, 1989; PRM-207-002, December 28, 1989
[51] General Motors Corporation: Comments and Response to Docket 89-20; Notice 1 December 4, 1989 89-20-N01-009
[52] Letter to Jerry Curry, National Highway Traffic Safety Administration from R. H. Munson, Ford Motor Company, regarding Request for Comments on Issues Relating to Rear Impact and Standard 207, November 29, 1989
[53] Letter from R. H. Munson to Administrator, National Highway Traffic Safety Administration regarding request for comments on seatback performance in rear impacts (January 22, 1993)
[54] R. W. Thompson, Dynamic Requirements of Automobile Seatbacks, (1993) SAE 930349
[55] United States Patent No. 5295729, High Retention Seatback, Inventor David Viano, Assignee: General Motors Corporation, March 22, 1994
[56] Letter from Thomas Baloga, Manager Safety Engineering, Mercedes-Benz of North America, Inc., to Barry Felrice, Associated Administrator for Rulemaking, NHTSA, March 17, 1992
[57] B. Lundell, et al., Volvo Car Corporation, Guidelines for and the Design of a Car Seat Concept for Improved Protection Against Neck Injuries in Rearend Car Impacts (1998) SAE 980301