ALTHOUGH SAFETY IS A BASIC CONSIDERATIONin all aspects of automotive engineering, it is afact of life that safety advances are not uniformlyaccomplished. Some essential aspects of motoristprotection have in the past, and probably will in thefuture, continue to be greatly outstripped by advancesmade in other areas. In some instances, the designchallenge simply exceeds current technology; onother occasions an adequate safety standard and con-certed industry interest can correct obvious safetydeficiencies. For example, although improvedtires resulted only after new materials evolved, agreatly improved motorist restraining systemresulted from industry initiated research that cul-minated in a standard requiring installation of com-bination cross chest lap belts for all outboard frontseat locations.

During the past 20 years, new materials andtechniques have improved the comfort and wearresistance of automotive seats while simultaneouslyreducing their weight and cost; however, significantsafety related improvement in seat design duringthis period has not been accomplished. A summaryof findings from prior research (l)* published in1966 classified a structurally redesigned IntegralSeat with built-in S-point belt restraint as criticallyimportant for reduction of motorist injuries; thissummary also pointed out the lack of safety-seat

*Number in parentheses designate Referencesat end of paper.

760810

Automotive Seat Designand Collision Performance

D. M. Severy, D. M. Blaisdell, and J. F. KerkhoffSevery, Inc.

research up to that time. Although some researchhas been conducted since that time, the developmentof a safety seat still has not been accomplished. Inthe same study special devices, including the airbag, were rated as only of moderate relative im-portance.

After 10 years of government regulated safetystandards and nearly that many years of intensiveair bag development sponsored by both governmentand industry, the consensus of many automotivesafety researchers in Europe (2), (3) and elsewhereis to change the emphasis back to development ofactive restraint systems and to increase effective-ness by means of mandatory use laws. Air bags,if used, would serve a supplementary function inconjunction with active systems. Progress insafer seat design has been impeded throughout adecade of automotive safety standard making, andmany lives have been lost that could have been fullyprotected with a fraction of the inventive genius andfunding lost to air bag development. A basic commonsense approach to motorist protection from collisiontrauma calls for special attention to design of thecritically important structure nearest the motorist,his seat.

A vital consideration of seat design is its cap-acity to protect motorists, to the extent practical,from all types of collision injury exposures. Thispaper provides basic design data for crashworthyautomotive seat systems with integral active re-

Eighty-five laboratory full-scale force-deflec-tion tests were conducted on passenger vehicleseats, foreign and domestic, for purposes of evaluat-ing specific resistance to a collision environmentand mechanisms of collision induced seat distortion.These tests evaluated seats that span the past thirtyyears; additionally, seat design studies were con-ducted evaluating basic features of automotive seat-ing during the past eighty years.

Data from full-scale collision experiments andfrom a large number of actual accidents facilitatedthe establishment of seat design criteria for greatlyimproved collision performance. Evolution of seatand head support standards in the United States andEurope are presented with evaluation of their rela-

2551

tive significance to the requirements of automotiveseat collision performance.

The foregoing research provided foundation formodification of a production automobile seat into anintegral safety seat, based on a design concept thatminimizes bending moments during collision. Themodified seat was subjected to the same laboratorytest procedure applied to the 85 non-modified pro-duction seats and results of its performance isgiven.

Design concepts are presented that would serveto mitigate undesirable seat distortions during col-lision and thus improve seat restraint capabilitieswithout compromising the important factors of com-fort and cost.

2552

straints, as determined from the authors’ collisionresearch and laboratory studies as well as experi-ence gained from investigation of relevant accidents.

BACKGROUND

The first automotive seat, like the firstautomobile was an adaptation from the horse-drawncarriage. Springs to absorb road shocks wereprimitive, effective padding was non-existent andseat adjustability had not yet been considered. Com-mencing around 1900, motorist safety while travel-ling over rough roads was improved by developmentof deeply contoured seats that reduced the likeli-hood of motorist ejection as the car body pitchedand rolled. Generally, however, little considera-tion was given for the safety of the occupants,Fig. 1.

Front seat fore-and-aft adjustment was notavailable until about 1929 when adjustable frontseats for the driver became a feature of higherpriced automobiles. Occupant comfort was givenincreased attention as engineering problems con-cerning motor vehicle performance and reliabilitybecame more effectively managed. Improvementsin seat design continued and by the mid 1930’s,seats, tracks and runners closely resembled thoseof the mid 1960’s. During the period between thethirties and the sixties, the only significant in-novation in seat design was the introduction of powerseats and adjustable reclining backrests duringthe early 1950’s, Table 1. Seatback height reachedreasonable levels in the late 1960’s but by the mid-seventies the height of backrests on many modelshad declined to levels less effective than thirtyyears ago. Seatback strength has not increasedsignificantly over the past thirty years and remainsinadequate to resist even moderate collision forces.The remarkable safety improvement facilitated by -the backrest head support standard FMVSS 202 hasbeen compromised through failure to upgrade cri-teria to maintain performance commensurate withintent. Seventy percent of adjustable head restraintsare used in the downmost position (4). Little ef-fective protection is afforded the motorist unlessthe head restraint is positioned behind or slightlyabove the head and remains in such support posi-tion during collision.

D. M. SEVERY

a seat also should have adequate structure forhousing safety and convenience accessories. Trade-offs are imposed by this complex mix of require-ments; however, in seat design we should no longeroverlook the requirement for a reasonably safe,collision resistive structure with built-in activerestraint system.

SEATING CATEGORIES - Automotive seatsfor passenger vehicles have a number of basicconfigurations and sizes depending on intended useand location. Position adjustment depends onfactors such as location (front or rear): availabilityof comfort features, including center armrests,depends on vehicle price, type, purpose and countryof origin.

BENCH SEAT - SOLID BACK - Standard andcompact 4-doer sedans are frequently equipped withsolid-back berth seats, front and rear. The frontseat has a single adjustment mechanism and theentire seat is usually adjusted according to the

BJtLAWt v”

Fig. 1 - Driver ’s seat , horseless carriage

TABLE 1

SEAT DESIGN EVOLUTION

INTRODUCED ITEM

1890 - 1900 Automotive Bench Seats1900 - 1910 Deep Bucket Seats1910 - 1915 Fold-forward Backrests1910 - 1915 Console Between Seats1910 - 1915 Pedestal Seat1915 - 1920 Swivel Seat

SEAT FUNCTION AND CONFIGURATIONS 1920 - 1925 Fold-down Armrest1925 - 1930 Fore-and-aft Adjustment1950 - 1952 Power Seats

It is not a simple engineering task to design a 1960 - 1963 Optional Head Restraintsgood automotive seat; it must provide comfort, 1968 Integrated Head Restraintstyle and safety, and yet be sufficiently light weight 1969 Standard Head Restraints

to facilitate vehicle fuel economy and to minimizecollision inertial stresses. Seat designs and mater- _ _ _ _ _ - - .----- -

EXAMPLEPhilion*Thomas*[Model-T Ford*Wescott*Argo Electric*Cole*Dusenberg*Viking*PackardAll U.S.VolkswagenAll U.S.

ials must be affordable and durable to give accept- *Based on authors’ study of vehicles made available through coopera-able service over the life of the car. In addition to tion of Harrah’s Automotive Museum, Reno, Nevada.provisions for comfort and position adjustments,

AUTOMOTIVE SEAT DESIGN AND COLLISION PERFORMANCE

needs of the driver. A bench seat, if adequatelydesigned for three occupants, must be capable ofsustaining a rearward static moment, calculatedabout the H-point of the seat, equal to three timesthat of a single seat.

BENCH SEAT - SPLIT BACK - Fold-forwardbackrests provide access to the rear seat of 2-doervehicles. Since only the upper portion of the seatis divided, the fore-and-aft adjustment can accom-modate only one person. Backrest angle, however,can be made adjustable according to the individualneeds of driver and passenger.

BUCKET SEATS - Contoured seats for indi-vidual occupancy are called bucket seats, althoughthis term originally applied to more deeply con-toured racing-type seats. The containment featureof deeply contoured bucket seats has been identifiedby the authors and others (5), (6), (7) as a consi-deration in design of a safer seat, owing to improvedlateral retention; however, the extent of contouringmust be based on consideration of comfort andpracticality as well as safety.

Adustable backrest angle is commonly availableand provides improved comfort and reduced musclefatigue. Direct attachment to the seat of both lapand shoulder belts is a safety and convenience goalthat has been identified previously, (l), (5)) (6),(7), (8) and is further evaluated in this study.

FOLDING SEATS - These seats require specialdesign considerations to allow them to be foldedflat when hauling cargo. These requirements includespecial sizing, latching devices and flat, durablecargo surfaces. Seatback height and strength aswell as provision for isolating cargo are collisionsafety factors to be considered.

PEDESTAL BUCKET SEATS - These seats arecommon to buses, vans, motor homes and trucks.In addition to the normal fore-and-aft position ad-justments, variable backrest angle and swivellingmechanisms are sometimes provided. Because of

2553

their elevation, direct restraint system attachmentrequires special design considerations.

FIXED, BUS-TYPE BENCH SEATS - Althoughsimilar to the rear seats of passenger sedans theseseats are elevated and generally provide openspace beneath; structural limitations and remotenessof seat from floor increase the difficulty of directrestraint attachment. Seats used in buses thattransport children require special considerations,(91, (10).

SEAT SYSTEM COMPONENTS

A brief description of seat components willallow a better understanding of basic seat require-ments and the special seat structure necessary foradequate passenger protection from collision trauma,Fig. 2.

STRUCTURAL FRAME MEMBERS - The seatframework is usually constructed of steel that hasbeen formed into tubular configurations or of stampedor rolled sheet metal. Historically, the functionof this structural backbone has been limited to pro-viding shape for the cushioning members and supportfor its own weight and that of its occupant. Rede-sign and strengthening of the seat framework inconjunction with its anchorages can provide theforce resistance necessary for occupant restraintduring moderate and severe front, side and rear-end collisions.

NON-STRUCTURAL SEAT MATERIAL - Cushions,springs and upholstery provide the necessary meansof load distribution between occupant and seat frame;they also provide contour and geometry necessaryfor occupant comfort. A redesigned integral seatwould include energy absorbing (E-A) padding atthe sides, top and back to provide additional forcemoderation and load distribution during collision.This concept is typified by the Crandell-LibertyMutual Survival Car II (11).

D RESTRAINT/INTEGRAL OR ADJU.STAlsLE/

UPHOLSTERY

STRUCTURAL FRAMEWORK

LUMBAR CONTOUR ADJUSTMENT

ACKREST ANGLE ADJUSThfENT

SEAT/BACKREST JUNCTIONw c PIVOT ARM

PIVOT FOR REAR SEAT ACCESS

Fig. 2 - Seat nomenclature

LFORE AND AFT AND V.ERT/CAL ADJUSTMENT

2554

SEAT ADJUSTMENT MECHANISMS - Thesemechanisms should be strengthened to withstandcollision forces as well as the rigors of everydayusage. Considerations of driver anthropometricdifferences necessitate a multiplicity of seatadjustments to assure that a given seat providesthe multiple functions of driver positioning forcorrect reach and view, as well as for adequatecomfort. Desired seat position may be accomplishedby means of longitudinal, vertical and tilt adjust-ments . Other adjustments include backrest angle,head restraint position and lumbar support stiffness.

Head restraint height adjustment is a commonfeature of current production seats. Unfortunately,many recent seat designs provide no head supportprotection from even minor rear-end collisionswhen the head restraint is in its most commonly used,retracted position. Proposed legislation (12) wouldmodify head restraint requirements to ensure pro-per utilization by preventing mis-adjustment orcomplete removal. Backrests with integral headrestraints eliminate adjustability deficiencies, butshould be designed to protect 95th percentile adultmale occupants. Adjustable headrests should extendto 80 cm (32-in) and not allow adjustment below70 cm (28 in); the headrest in its adjusted elevatedposition must not collapse from head impact.

SEAT ANCHORAGES - Most vehicle designsdepend on seat attachments at the floor or at thesill and tunnel to transmit forces between thevehicle and the seat. This anchorage is generallyinterposed between the seat adjustment mechanismand the vehicle floor pan or lower structure.

Under static conditions, the seat anchoragetransmits compression, tension and shearforcesfrom the seat to the floor or side structure. Inthe event of collision or handling accelerations, theresulting forces are transmitted in reverse directionfrom floor to seat. The seat anchorage structures

D. M. SEVERY

and attachments require a design of adequate strengthto accommodate seat and occupant inertial forcesidentified specificaIly in other sections of the paper.Besides the usual floor, sill and tunnel anchorages,other potential anchorage locations for strengthenedseat systems include side and roof attachment.

SEAT DESIGN CONCEPTS

Restraint compliance, is the change in re-straint geometry induced by motorist’s inertialforces during collision. For example, a lap beltmay initially course from its floor anchorage to-ward the lap of the wearer at 45 degrees but as afrontal impact develops, this angle is reduced owingto a combination of factors that result in theoccupant’s buttocks being compressed downward andforward on his seat as the belt restraining forcesincrease, (13). Similar ily , variations in supportforce, restraint angle and resulting backrestpressure modulations occur for the seated occupantas the seat backrest undergoes restraint complianceduring a rear-end collision. This is illustrated forrestrained and also for inadequately restrainedoccupants, by the geometric areas within the curvesdepicting displacements of occupants relative totheir vehicle, Fig. 3. Also shown is the addedphysiological trauma associated with unstructured,inefficient restraint compliance. Variations in occu-pant collision-induced accelerations (slopes, Fig. 3)depend on the effectiveness of occupant restraintswhich determines in large measure the traumaduring ride-up/ride-down accelerations; the mech-anism of transmission of accelerative forces re-present the other operative factor for such trauma-tic exposures. The problem faced by a seat designeris to determine the force resistive levels, and there-fore the degree of collision severity, a specific seatdesign should be able to accommodate before back-

TIME, MILLISECONDS

Fig. 3 - Relative abruptness of occupant “Ride-down/Ride-up ,I’according to efficiency of restraint

AUTOMOTIVE SEAT DESIGN AND COLLISION PERFORMANCE 2555

rest restraint compliance reaches values whereoccupant forced displacements expose him to seriousor critical injuries.

When not faced with the realities of cost andoperational practicality, as well as the need to pro-vide design features that favor public acceptance,a simplistic approach is to set safety design criteriaat some arbitrarily high level, one considered suf-ficient to encompass virtually all probable collisionexposures. Such arbitrary criteria is insensitiveto orders of priority and cost for safety design im-provement and disregards the interactive responseit may impose on other related, or concurrentlyimportant, passenger and operational safety features.

The front seat backrest and the steering columnhave in common the engineering design problemsthat result from dealing with cantilevered structuresacted upon by occupant collision forces. Additional-ly, backrest angles of 15 to 25 degrees increasedesign difficulties by incorporating angles that allowless efficient crash force moderation.

LABORATORY SEAT TESTS

Passenger vehicle seats of differing makevehicles are as varied structurally as the motorvehicles within which they are mounted. Aside fromtheir apparent commonalities consisting of seat,backrest, head support, covering, padding, springs,and frame, the multiplicity of design and sizevariations account for their significantly differingweights (under 9 kg to over 45 kg or about 20 toover 100 lbs.) height of backrests (from 51 cm toabout 76 cm or from 20 to about 30 in) and maximumbending moment before excessive backrest deflect-ion (from 45 m-kg to about 95 m-kg or about 4000in-lbs to 17,000 in-lbs), Fig. 4. As remarkableas these variations would appear, they representlittle difference in motorist protective capacityowing to the fact that none of them are capable ofeffectively resisting motorist inertial forces forany substantial impact exposure.

Based on laboratory tests of seats from carslarge and small, foreign and domestic, and fromvehicles 30 years old to near new, backrest strengthswere found to be remarkably alike, Fig, 4. Force-deflection performance curves of representative pro-duction seats as well as recommended performancefor passenger vehicle seats capable of protectingtheir occupants during severe collisions are shown,Fig. 5.

INTEGRATED SEAT - The concept of an in-tegrated seat for motorists has been consideredand evaluated theoretically; experimental seatshave been constructed and tested experimentally,(I), (2), (5), (6), (7), (II), (14). In general, theapproach has been to design an entirely new seat,inducing the argument that practical aspects ofmanufacturing, occupant comfort and similar design

burdens remain yet unsolved. With this in mind,the authors redesigned a Volvo production bucketseat into an integrated safety seat. This approachshould facilitate recognition by automobile manu-facturers and the Federal Government’s safetystandards making authority, that the goal for greatlyimproved motorist safety is reasonably attainablethrough development of an integrated front seat.

The Volvo seat was stripped of its upholsteryand subjected to an evaluation of modifications con-sidered essential to developing performance speci-fications for an integrated safety seat, Fig. 6.Next, this production seat frame was modified toprovide the added structural support required forthe special protective hardware, Fig. 6b.

Seat Modifications - Changes were made in theproduction seat by additions of components to aug-ment existing safety and comfort features and tointroduce new protective functions as follows:

(a) High section-modulus tubular steel back-rest, from seat attachment through head support.

(b) Double seat tracks, for more positiveanchorages.

(c) Lap and cross-chest safety belt inertialreels mounted to seat frame for ease of fasteningand for optimum occupant restraint for all adjust-ment positions.

(d) Energy absorbing back panel, to moderateand pocket occupant inertial loads during mediumand high-speed rear-end collisions and to provideknee pocketing for kinematic control of rear seatoccupants thrown forward during frontal collisions.

(e) A pair of seat-mounted inertial reels forbelt fabric which connects the base of the seat atits rear to the roof; the belt fabric is passed throughthe backrest to the roof anchorage. This arrange-ment allows the seat to be adjusted fore-and-aftand folded for entry accommodation; however duringa front or rear-end collision, the dual “safetybelts” are capable of immediate seat inertial snub-bing.

(f) Deeply contoured bucket seat geometry toassure occupant positive lateral support and toimprove comfort.

(g) Retention of the most advanced comfortand safety features of backrest angle adjustment,lumbar spine firmness adjustment and louvered see-through head restraint.

Most prior integrated seat concepts haveutilized the backrest cantilever principle whichnecessitates strengthening floor and seat anchoragesalong with seat and backrest framing in an effortto combat the extreme bending moments, especiallyattending front and rear -end collisions, (7)) (8))(14). The advantage of this approach is that seatfore-and-aft positioning and backrest folding foraccess to the rear seat can be accommodated with-out roof or side attachment; disadvantage is that

2556 D. M. SEVERY

1940 1950 1960 1970 1960Y E A R

z 1200-c.3 _1104.000, (RECOMMENOEO STRENGTH) \\a\\\\

$2 IOOO-LT 1 ~87,000,

U-J = ,,&?~k-i

Fig. 4 - Automotive seat strength and backrest height(PREVAILING STRENGTH) variations over the past thirty years

~.~\\\\...~\\~

1940 1950 1960 I970 1960Y E A R

Fig. 5 - Backrest force-deflectionautomobiles, foreign and domestic,

data for 85

* STATIC REARWARD FORCEAPPLIED 35 CM ABOVESEAT/BACKREST JUNCTION

production BACKREST D E F L E C T I O N , CM (IN)

large and small sizedvehicles

it is a very inefficient method of resisting largeforces owing to the massive increases in structurerequired to offset extremes in bending moments.The authors found that many production seats couldresist between 900 and 1800 kg force (about 2000 to4000 lbs) horizontally rearward or forward at theseat rail. If these floor anchorages were onlyslightly improved, and connected by belt webbingto the roof, the cantilever design could be replacedby the basically greater efficiency of the tensionsemi-hoop design spanning floor to ceiling. TheExperimental Safety Vehicle by Opel also uses aform of roof anchorage for its front seat backrests,(2). Encouragement was given to the practicalityof this concept by a preliminary test of roof strengthof a mid-sixties 2-doer hardtop sedan. This un-modified roof structure withstood over 1800 kg(4000 lbs) horizontally rearward at a localized back-rest to roof attachment location, without significantdownward crush.

The integrated seat was subjected to laboratory

tests along the lines previously described as shownby Fig. 8. The improvement in force-displacementover non-modified production seats is shown by thedotted curve of Fig. 5. Considering the nature ofchanges necessitated by using an existing seat, itis apparent that a somewhat lighter seat could bemade even stronger if it were an original designrather than a retrofit. The composite designfactors for a remarkably stronger, attractivelycontoured seat are shown by Fig. 7. Extensivecrash testing of such new concepts are recommendedfor sound development before they are used in pro-duction vehicles.

SEAT COLLISION PERFORMANCE

Relative to vehicle safety, performance connotesa level of attainment, a plateau from which conceptsfor improvement may be assessed, both as to prac-ticality and possible adverse influence on other safetyrequirements. Like the occupant that uses it, a

AUTOMOTIVE SEAT DESIGN AND COLLISION PERFORMANCE 2557

2558

Fig. 7 - The Integralby the authors

Safety

D. M. SEVERY

ROOF ATTACHMENT: ;;;

ROOF ANCHORED BELTS TRAVERSEDOWNWARD THROUGH SEAT

INTEGRATED SEE- THRU HEAD RESTRAINT

PADDED LATERAL SUPPORT

BlJlL T- /N 3 PO/NT BELT /

BACKREST PANEL DEFORMABLE MA

ROOF ATTACHMENT INERTIAL

EXTENDED LATERAL STRUC

ROCKER S/L L

Seat conceptualized and tested

Fig. 8 - Integrated seat during testing; 2268 kg (5000 lb)force applied rearward

seat has rather specific collision force tolerances:exceeding its design criteria allows crash forcesto yield or fracture whatever component of the seatis most susceptible. This collision response iscommon to all seats, as determined from destruc-tive tests to over 85 different automobile seatsmounted on their floor pans. Although individualdesigns determine which components may fail first,their level of susceptibility is remarkably similar.Perhaps the foundation for this similarity in seatstrength levels is generic to the basic design require-ments that were dictated long before collision forceswere identified as factors for consideration. Forexample, an adult male can apply 90 to 135 kg (200to 300 lbs) force to the backrest during emergencybraking. If passengers also brace for a possiblecollision, the backrest of a bench seat can be calledupon to resist as much as 275 kg (600 lbs) force,It is understandable, therefore, that seats in theforties and fifties had backrest yield resistance ofabout 275 kg (600 lbs) even though they were notdesigned in a period when collision safety was aprominant consideration: incomprehensible is thefact that seats in the seventies show no significantimprovement.

The basic collision performance criteria thatapplies to a seat is its resistance to backrest yieldand its ability to transmit forces through the seatto its anchorages. Although seat design has in noway kept pace with advances made in other safetyrelated areas, there are some notable exceptions;certain Mercedes and Porsche automobiles, forexample, attach lap belts to the seat, rather thanusing the less satisfactory arrangement of flooranchorages. Volvo and Saab have provided see-through head restraints that improve visibility. Thetrack record of most vehicles, however is notimpressive. In general, backrest strength andheight has not improved, possibly because the needfor stronger, full-support backrests is not fullyunderstood by regulatory agencies and those makingdesign decisions.

SEAT COLLISION PERFORMANCE - FRONTALCOLLISIONS - It is becoming increasingly apparentthat passive restraint systems alone cannot protectmotorists from the varied exposures encounteredduring motor vehicle accidents (2), (3). Systemsthat protect during a barrier-type crash may becompletely ineffective if the same frontal collisionis accompanied by one or more minor impacts or

AUTOMOTIVE SEAT DE,‘,IGN AND COLLISION PERFORMANCE 2559

an upset. The cross-chest lap belt restraint system,on the other hand, provides effective motorist pro-tection during most collisions or combinations ofcollisions, including upset. If an integral three-point restraint system is available, in conjunctionwith the strengthened seat to which it should beattached, it can provide levels of protection unat-tainable with any other single system, howevercostly or complex. In addition to minimizing oreliminating impact forces to the vehicle interior,the combined restraint system appreciably reducesthe forces that would be applied for a lap belt onlyprotective system, (15).

One advantage claimed by air bag proponents isthe additional ride-down distance provided as themotorist crushes forward relative to the vehicleinterior. Direct attachment of belt restraints tothe seat minimizes uncontrolled belt slack and atthe same time allows the designer to incorporatebelt pre-stressing and other ride-down improve-ments for the belt and seat anchorages. The beltsystem can thereby provide maximum protection forfront-end collisions and also provide more adequateprotection during the wide range of other collisionexposures, including moderate to severe rear-endcollisions by keeping the occupant in the seat. Evena floor mounted lap belt can provide considerableprotection under these conditions, (16).

Rear seat occupants that fail to fasten theirbelt would obtain some degree of passive restraintfrom a strengthened front seat backrest. The kneepocketing concept evaluated and described previously(6), will add considerably to rear seat occupants’collision protection by controlling posture duringtheir “second collision. ” The spacing between rearoccupants and front backrest provides a time delaybefore the rear occupants strike the front backrest;therefore, front seat occupant ride-down would notbe compromised significantly from subsequentimpact to the backrest by the rear seat occupant.Rear seat occupant protection for all but rear-endcollision exposures can best be accomplished bymeans of active restraint systems.

OCCUPANT RESTRAINT WITH A RECLINEDSEAT - The cross-chest lap belt is less effectivein front-end impacts where the passenger hasreclined his seat; the torso slides forward, shiftingthe lap belt upward across the viscera. When beltsnubbing eventually occurs, forces are transmittedto portions of the body unable to sustain them with-out exposure to serious injury. Also, the neck orhead may strike the cross-chest belt in an ineffec-tive, if not dangerous manner. One solution is toprovide an additional pair of straps attached at thefront of the seat and passed upwards through posi-tioning guides. Before reclining the backrest, thehanging ends of the straps are pulled up betweenthe legs and fastened to attachment loops sewn to

the lap safety belt. This arrangement maintainsthe lap belt across the pelvic girdle during collisionand, for non-integral seats, reduces mal-alignmentof the cross chest strap as the torso flails forwardagainst it.

SEAT COLLISION PERFORMANCE - REAR-END COLLISIONS - The most frequently occurringtype of motor vehicle collision is the rear-end im-pact. For example, forty-nine percent of the 14.6million accidents involving motor vehicles in theUnited States during 1968 were same direction orrear-end type accidents; representing nine percentof the total number of fatal collisions, (17).

Seat backrest performance during rear-endcollisions parallels a condition of walking on thinice; minor torso inertial forces receive adequatesupport but as impact severity increases, theresistive support approaches negligible values. Themechanism by which this passive restraint is lostis generally unimportant insofar as its effect onmotorist kinematics is concerned. Torso inertialmovement does not respond differently with differingmechanism of loss of back support; it simply re-sponds inertially to fall-off of resistive force. Thus,whether backrest resistance is subsequently lostbecause of excessive backrest yield or by combina-tions of baclcrest yield and anchorage separations,the motorist inertial forces will act in the samemanner.

Backrests are slightly reclined for comfortand to assist with torso support. However, as theseat is forced to recline additionally during rear-end collision, the torso is predisposed to rampingup the plane of the backrest, Fig. 9. On reachingbackrest angles exceeding 45 degrees, the rampcomponent falls off according to the function “sin CYcos CX, I’ where alpha (a) is the backrest angle rear-ward from the vertical axis. Simultaneously, thebackrest support force, FSB, which accelerates

the motorist as the backrest bears against himduring a rear-end collision, falls off as a functionof backrest yield-angle, likewise depicted by Fig. 9.Obviously, a zero or near zero angle provides themost effective torso support by the backrest duringrear-ending and torso support tends to fall offthereafter, as a cosine function of increases in thebaclu-est angle.

These factors are particularly relevant forproduction seats involved in light to moderaterear-end collisions where bachest strengthsgenerally are adequate for those respective exposures.However, for most moderate to severe rear endcollisions, all production seat backrests deflect toangles providing no effective motorist support.This situation is illustrated by considering the re-lationship of backrest support provided the torso asa function of rear-end collision speed, Fig. 10.Sixty-five percent of the body weight may be used

D. M. SEVERY

I,I_---,

c IO 20 30 40 50 60 ‘70 RO

SEAT BACKiEST 4NGLE ,o< , DCWCES

T

/

Fig. 9 - Degradationof collision induced

as a minimal approximation of the torso andadjacent flailing body components that operate anyinstant to inertially act on the backrest and may becharacterized as the occupant inertial force, F .The seat backrest yield point, or point of maxizimbattiest resistive force, F

7, is reached when the

occupant inertial force plus he seat backrestinertia force exceeds FR as shown by F

FR’ Based on collision experiments (18’t;eFsI =

torso inertial force increases with collision speed,in the manner shown by Fig. 10. Regardless ofspeed of impact, the backrest can provide only agiven maximum resistance to yield; however, asrear-ending speeds increase, the collision severityis reached where the baclu-est can at best supportsolely its own weight, but none of the occupant,Fig. 10. Thus the effective backrest strength isdependent on a combination of backrest resistanceto yield and backrest weight, referred to as back-rest weight, referred to as backrest inertial yieldresistive force. The lighter the weight of a seat,relative to a given resistance to deflection, thebetter able the seat to resist torso displacementduring rear-end collision.

Given a sufficiently severe collision, any seatwill fail; the type of failure however, depends ondesign. Rear-end collisions induce five basictypes of failure; a particular collision exposure fora particular seat design may result in one or acombination of these five types of failure:

(a) Excessive backrest yield(b) Track-runner vertical separation(c) Track-runner longitudinal separation(d) Compressive crush at seat base(e) Floor yield at seat attachmentAll automotive seats have collision induced

failure modes that are caused by moments andforces exceeding one or more of the seat compo-nent yield points. Critical reaction requirementscan be calculated for various occupant sizes andacceleration exposures using free body analyses ofthe seat system, Fig. 11.

For rear-end collision exposures, the additionof a roof anchorage for the backrest serves todistribute forces and considerably lessens design

of backrest support as functiondeflection

requirements for individual components. For ex-ample, the extremely difficult design task ofproviding 75,000 inch-lbs yield resistance at thebachest pivot for a 50% adult male in a 30G seatsystem can be easily managed by utilization of aroof ant hor . If one-third of the 6540 pound hori-zontal force is applied at the top of t,he seat andacts 32 inches above the backrest pivot, we now havethe following moment at the pivot arm:

MI = 75,000 - (32) (2180) = 5300 in-lbs, areduction to 7% of the original required bendingmoment. Most production seats can provide thislevel of bending resistance without need for modi-fication. With a roof attachment, the maximumbending moment will be at a higher elevation on theseat and in a location of the backrest free of com-plications of pivots and adjustment mechanisms.Correspondingly, the reduction in reaction strengthrequired at R , RH and RF, if a roof anchorage isadded, prove es a requirement of only 2%, 65%,*%and 2% respectively of the values necessary withouta roof attachment.SEAT COLLISION PERFORMANCE - SIDE IMPACTS -Direct side impacts into the passenger compartmentrepresent the gravest danger to motorists at a givenspeed of impact for any type of collision, (18).Usually less than a foot of intervening structure,much of which is non-structured space, separatesthe motorist on the impacted side from the frontend of the impacting vehicle. During collision,the near-side occupant suffers a considerably moresevere acceleration than does the vehicle in whichhe is riding. This impact exposure can be lessenedsomewhat by increasing the amount of side structurestiffness and thereby minimizing passenger compart-ment intrusion. However, the point of diminishingreturn is soon reached as intervening structure isadded, since crush distance is still limited, anddelayed occupant response serves to magnify theresulting exposure, A considerably simplersolution is to attach the motorist firmly to a deeplycontoured seat by means of an integral 3-point beltand to provide intermediate structural membersbetween striking car and seat to cause the seat,

AUTOMOTIVE SEAT DE:XGN AND COLLISION PERFORMANCE

IL 400-

u

BACKREST PEAKRESISTAANCE TO YIELD

0 2 0u44093 ($33) 14%

100(124) 162 I)

REAR-END COLLISION CLOSURE VELOCITY, KWHR (MPH)

Fig. 10 - The relationship of backrest torso support, a sa function of rear-end collision speed

3-1 8 , 0 0 0 -$ ( 6 9 , 0 0 0 )-

iz

2

0 IO 20 3 0 4 0COLLISION ACCELERATION, G’s

2561

Fig. 11 - Collision induced seat stresses, rear-endcollision exposure

with occupant attached thereto, to be acceleratedmore promptly but less abruptly.

Analysis of the velocity-time profile of atypical side impact collision, Fig. 12, providesfurther understanding of the nature of accelerativeexposure and resulting injury mechanism as itexists for the unrestrained struck motorist. Thisgraph also shows the remarkable reduction inoccupant acceleration that can be accomplished ifthe seat is structured and interlocked with sidepanels so that it is accelerated more promptlyfollowing initial contact by the striking vehicle.This improved side impact acceleration, or “ride-

up, ” is similar to the “ride-down” concept ofprotection from frontal collisions, identified byprior publication, (19). The more promptacceleration also reduces the impact abruptness or“Stapp’‘-factor. Since the combined weight of theseat and the occupant is often less than 90 kg(200 lbs), it is not necessary to provide significantlyheavier structure than already present to accomplishthe objective of prompt seat acceleration during acollision. It is only necessary to position thestructure at the proper elevation and location toallow more direct collision force application tothe seat structure to occur before substantial in-

2562 D. M. SEVERY

50 K#/l

kl;

G8

‘MAXIMUM ACCELERATIONS (APPROX.)0 STRIKING VEHICLE C.G. ,..... .._......... ._... 20 G

\t IO 0 STRU C K V E H I C L E C.G ._...... 20 G

-(33) OUTER SURFACE _......_... + @ G? INNER D O O R S U R F A C E 1706

;,.,li /‘m f : : ;,;z;;;;;pzg(,GENERGY A B S O R P T I O N 6 0 G

,, 3tfl’@ 4, u FULLY RESTRAINED

I-X-CliPANT IN INTFGRAI““““. _.. , . . . ,.. . L.,I.__

S E A T . . . __. __... ._. ._. __ .__. 30 G

F i g . 1 2 - I n t e g r a l s e a t , side-impact exposure analysis

ward crush has taken place. Additional motoristforce moderation is provided by the pocketingeffect of the integrated seat. This seat side-struc-ture tends to shield the motorist from directimpact by his vehicle side structure as well as tominimize “slack” between the motorist and hisrestraint system. This shielding also reducesmotorist exposure to punctures and shear forces.

ROLLOVER PROTECTION - Injuries andfatalities during rollover accidents occur mostfrequently as a result of ejection (20), (21); abasic requirement for occupant restraint systemsis to retain the occupant within the vehicle duringupset. Even if adequate retention is achieved,protection is compromised if there is inadequatesupportive roof structure.

Roof structures are sometimes flattened duringupset sufficient to dangerously reduce the motoristsur viva1 space. This crush can be reduced consider-ably by constructing the seat backrests with suf-ficient strength to act as central pillars for theroof. A strengthened seat with integrated headrestraint of a height necessary for adequate headsupport for taller persons 80 cm or more (32 in)is recommended if central roof collapse resistanceis to be increased by backrest structural support.Seat backrest structure of sufficient strength andheight to answer the requirements imposed byother collision exposures will also prevent completecollapse of roof structure in nearly all collisionexposures.

STANDARDS AND RECOMMENDED PRACTICES

In November 1963, a Society of AutomotiveEngineers Committee report on passenger seatsand adjusters was approved. This action, for thefirst time, extended the concept of recommendedpractices and performance standards to includeautomotive seats. Two tests were specified byrecommended practice 5879, the first of whichestablished minimum strength requirements forhorizontal inertial seat loadings for front and rearimpacts. This 20G specification corresponds toapproximately a 900 kg (about 2000 lbs) seat an-chorage loading for a typically large domesticbench seat and serves to evaluate the retentioncapability of the adjuster mechanism and seatanchorages. The second test prescribed by SAF5879 concerned backrest strength and specifieda minimum moment of 4250 in-lbs. Although thescope of the recommended practice included anintent to submit it to a “continuing review” nosubstantial changes were made until July 1968.

In 1965 the Federal Register published GeneralServices Administration (GSA) Federal Standard515-6 governing “Anchorage of Seats. ” This initialseat standard became effective in 1966 for 1967 mo-del automobiles. GSA adopted basically the originalSAE recommendations with no major changes.Although this transfer of 5879 from an SAE Recom-mended Practice to a GSA standard was applicableonly to government purchased vehicles, it wasunderstood to be the forerunner for a standarddirectly affecting every passenger car sold in theUnited States.

AUTOMOTIVE SEAT DE.;IGN AND COLLISION PERFORMANCE 2563

In 1966, by act of Congress, the Department ofTransportation (DOT) was added to the FederalGovernment. The 1965 GSA 515-6 Standard, whichwas actually the SAE Recommended Practice of 1963,was adopted by DOT in January 1968 as FederalMotor Vehicle Safety Standard (FMVSS) 207. TheFMVSS 207 established backrest strength forstandard passenger vehicles at 3300 in-lb, differinginsignificantly from the GSA/SAE 4250 in-lb value,owing to a change in reference systems. FMVSS207 references the Hip Pivot or H-point (as describedby SAE J826b) whereas the SAE 58’79 and GSA 515-6used a reference pivot point that was about 20 cmlower (8 in) at the interface between the seat frameand adjuster. Although 3300 in-lbs may appear tobe an impressive value, production seats from thenineteen forties and fifties tested by the authors werefound to substantially exceed this standard. FMVSS207 included the requirement that the fold-forwardbackrest locks withstand a 20G minimum inertialload which represented a modest improvement. In1972, FMVSS 207 was amended to include multipur-pose passenger vehicles, trucks, and buses. Addi-tionally, the standard was expanded to include re-quirements relating to rear seats.

Head restraints, whether separable, or integralwith the front seat backrest were regulated byFMVSS 202 in 1969. This standard requires thehead restraint to be capable of resisting a 200 poundforce applied horizontally to it and actually consistsof a more severe loading to the backrest pivot thandoes FMVSS 207, to reduce the chances of headsupport failure before backrest failure.

In Europe, seat strength standards applicableto non-exported vehicles were enacted by the Councilof European Communities in 1974; these arebasically the same as FMVSS 207, except for anincrease in the minimum moment resistance ofthe backrest from 3300 in-lb to about 4700 in-lb(54 m kgf), both with respect to the same H-pointreference.

Prior to the advent of the automotive standardsmaking authority by the Federal Government, theautomotive industry was largely self-governed,relative to implementation of safety concepts.Slow, methodical but nevertheless significantprogress was made during this self-governed period,as pointed out in a prior publication, (19). Theemphasis was on operational and performancesafety; accordingly, collision safety advances werelimited.

Following the mid-sixties, the responsibilityfor progress in collision safety was taken over bythe Federal Government and assessment of theprogress made in this more recent period dependson the specific safety category being considered.In general, commendable improvement in collisionsafety has occurred during this period of regulationby the National Highway Traffic Safety Administra-

tion (NHTSA). However, with respect to automo-bile seat collision safety, little progress has beenmade. A near obsession with air bag developmentregrettably has diverted a tremendous amount ofresearch time and resources from the readilyachieveable goal of making the automobile seatcrashworthy. As a result, many automobilesbeing manufactured a decade after the onset ofFederal Government standard making still haveseats no stronger than they were during the pre-regulatory period. Any real improvements madein seat design have been on the initiative of themanufacturers because the seatback standardsrelating to strength have remained virtually un-changed. The presence of an inadequate, seldomupgraded standard limits initiative of automotivemanufacturers because of the implication thatsatisfactory conditions prevail.

SUMMARY OF FINDINGS

1. Improved automotive seat systems should pro-vide adequate structure and built-in active restraintsto insure a reasonable degree of protection fromcollision forces. Seats need adequate contour toprovide effective support and sufficient adjustmentsto meet the varied and changing requirements oftheir occupants. Redesign and strengthening of theseat framework and anchorages is required fordirect attachment of lap and shoulder belts and toprovide the force resistance necessary for occupantrestraint during moderate and severe front, sideand rear-end collisions.2. All automotive seats develop collision-inducedyield or separation modes caused by forces andmoments from motorist and seat inertia when suchstresses exceed one or more of the seat componentyield points. Although the specific component of aseat that fails first may differ, the degree of sus-ceptibility of all seats is remarkably similar. Lab-oratory tests establish that production seats fromcars large and small, foreign and domestic, andfrom vehicles 30 years old to near new, have back-rest strengths remarkably alike. All are incapableof effectively resisting motorist inertial forces forany but light impact exposures without inducingexcessive yield and/or component separation.3. Variations in support force and restraint angleoccur for the seated occupant as the seat backrestundergoes restraint compliance during a rear-endcollision. The mechanism by which this passiverestraint is lost is generally unimportant insofaras its effect on motorist kinematics is concerned.Torso inertial movement does not respond dif-ferently with differing mechanism of loss of backsupport; it simply responds inertially to the degrada-tion in resistive force.

4. Intended headrest height requirements arenot met for many seats when the headrest is in its

2564 D. M. SEVERY

most commonly used, retracted position. Backrestswith integral head restraint should protect 95th per-centile adult occupants; it is preferred that head-rests be contiguous with the backrest and of fixedelevation; if adjustable, headrest adjustment shouldprovide extension to 80 cm (32 in) and not allowadjustment below 70 cm (28 in).5. Passive restraint systems that effectively con-trol motorist collision dynamics during a barriercrash may be ineffective if the same frontal collisionis complicated by multiple impacts or upset. Thecross-chest lap belt restraint system, on the otherhand, provides effective motorist protection duringmost collisions or combinations of collisions,including upset.6. Collision-induced occupant accelerationsvary according to the effectiveness of occupantrestraints. These variations in “ride-up” and“ride-down” velocity changes determine in largemeasure the extent of trauma during collision; themechanism of transmission of accelerative forcesrepresent the other operative factor for suchtraumatic exposures.7. The authors designed, constructed and labora-tory tested a high performance integral safety seatthat was made by structurally modifying an existingproduction seat design without compromising itsadvanced design comfort features. The roof-to-floor anchored webbing for backrest crash forceattenuation remarkably simplifies seat structuralrequirements because bending moments are de-creased more than ten-fold. By use of inertialreels this front seat conversion is accomplishedwithout inhibiting rear seat access for two-doorvehicles or backrest reclining or seat fore-and-aft positioning. Direct attachment of cross chest,lap belt restraints to the seat minimizes uncontrol-led belt slack and allows incorporation of belt pre-stressing and other restraint compliance improve-ments. Increased costs for this restraint systemconcept would be nominal considering the benefits,however extensive crash test evaluation of anysafety seat design is required prior to productionto make certain all safety design features act con-structively without degrading other aspect ofmotorist’s safety.8. The integral safety seat provides the basis foreffective protective measures against direct side-impact collisions. With the motorist comfortablyrestrained by a 3-point belt and seated within adeeply contoured seat, structural members betweenthe seat and outside door surface act, duringcollision, to accelerate the seat, with occupantattached, during the initial contact and crush phaseof the collision and therefore accelerate the motor-ist less abruptly. Additionally, this design mini-mizes “slack” between the motorist and his restraintsystem and shields him from direct puncture andshear forces.

9. The integral safety seat protective capabilityagainst frontal impacts is well established, androof crush during rollover can be considerablyreduced by taller and strengthened front seat back-rests serving as central pillars for augmentation ofroof support: with an integral seat-restraint system,regardless of the direction of impact, levels ofmotorist protection can be achieved that are un-attainable with any other single system, howevercostly or complex.10. Commendable improvement in collision safetyhas occurred during a decade of regulation by theNational Highway Traffic Safety Administration.However, with respect to automobile seat collisionsafety, effective progress has been negligible. Anear obsession with air bag development regrettablyhas diverted a tremendous amount of research timeand resources from the readily achievable goal ofmaking the automobile seat crashworthy. Althoughthe 3300 in-lbs backrest resistance feature of theFMVSS 207 sounds impressive, production seatsfrom the nineteen forties and fifties tested by theauthors were found to substantially exceed this 207principal criteria.11. Judged on any rational basis, whether as toinitial cost, maintenance costs, functional reliability,exposure to dangerous malfunction or lack ofeffectiveness for many types of collision exposures,the air bag comes up as a king-size loser when com-pared with the collision protection of the integratedseat which includes integral cross-chest lap beltrestraint. While the United States endlessly pondersthe air bag issue, the rest of the automotive worldhas reached the conclusion that cross-chest lapbelts in combination with mandatory use lawsrepresents the simplest, least costly and mosteffective motorist protection measure.

REFERENCES

1. D. M. Severy, “Collision Performance ofthe Motorist’s Compartment, ” Highway Safety Re-search Institute, University of Michigan, Ann Arbor,Michigan, April 1967.

2. Anon. , “Fifth International Technical Con-ference on Experimental Safety Vehicles, ” sponsoredby U. S. Department of Transportation, Washing-ton, D. C., hosted by the U. K. Department of theEnvironment, London, England, 1974.

3. K. Langwieder, “Car Crash Collision Typesand Passenger Injuries in Dependency Upon CarConstruction, ” Sixteenth Stapp Conference, SAENo. 720968, Society of Automotive Engineers, Inc. ,Warrendale, Pennsylvania, 15096, 1972.

4. J. D. States, et al, “Injury Frequency andHead Restraint Effectivenss in Rear-end ImpactAccidents, ” Sixteenth Stapp Conference, SAE No.720967, Society of Automotive Engineers, Inc. ,Warrendale, Pennsylvania, 15096, 1972.

AUTOMOTIVE SEAT DE! IGN AND COLLISION PERFORMANCE 2565

5. D. M. Severy, H. M. Brink and J. D. Baird,“Collision Performance L. M. Safety Car,” SAENo. 670458, presented at SAE Mid-year Meeting,Chicago, Illinois, May 1967.

6. D. M. Severy, H. M. Brink, J. D. Bairdand D. M. Blaisdell, “Safer Seat Design,” SAE No.690812, Proceedings of Thirteenth Stapp Car CrashConference, Harvard School of Public Health,December 1969.

7. F. W. Babbs and B. C. Hilton, “The Pack-aging of Car Occupants - A British Approach toSeat Design, ” Chapter 32, Proceedings of SeventhStapp Car Crash Conference, University of California,Los Angeles, California, October 1963.

8. D. M. Severy, H. M. Brink, J. D. Bairdand D. M. Blaisdell, “Active Versus PassiveMotorist Restraints, ” SAE No. 700424, InternationalAutomobile Safety Conference Compendium, Detroit,Michigan, May 1970; Brussels, June 1970.

9. D. M. Severy, H. M. Brink and J. D. Baird,“School Bus Passenger Protection, SAE No. 670040,Automotive Engineering Congress, Detroit,Michigan, January 1967.

10. A. W, Siegel, A. M. Nahum and D. E.Runge , “Bus Collision Causation and Injury Patterns, ”SAE No. 710860, Proceedings of Fifteenth StappCar Crash Conference, Society of AutomotiveEngineers, Inc. , Warrendale, Pennsylvania 15096,1971.

11. C. Clark and C. Blechschmidt, “HumanTransportation Fatalities and Protection AgainstRear and Side Crash Loads by the Airstop Re-straint,” Proceedings of Ninth Stapp Car CrashConference, Society of Automotive Engineers, Inc. ,Warrendale, Pennsylvania 15096, 1965.

12. National Highway Traffic Safety Adminis-tration, “49 CFR Part 571 (Docket No. 74-13;Notice 1)) Federal Motor Vehicle Safety Standards, ItFederal Register, Vol. 39, No. 54, Washington,D.C., March 1974.

13. D. M. Severy, J. H. Mathewson andA. W. Siegel, “Automobile Head-on Collisions,Series II, ” SAE Transactions, Society of Auto-

motive Engineers, Inc. , Warrendale, Pennsylvania15096, 1959.

14. D. M. Severy, H. M. Brink and J. D.Baird, “Backrest and Head Restraint Design forRear-end Collision Protection, ” SAE No. 680079,presented SAE Congress, Detroit, Michigan,January 1968.

15. L. M. Patrick, et al, “Impact Dynamicsof Vehicle Occupants, ‘I Tenth Stapp Conference,Society of Automotive Engineers, Inc. , Warrendale,Pennsylvania 15096, 1966.

16. F. Preston, “A Comparison of Contactsfor Unrestrained and Lap Belted Occupants inAutomobile Accidents, ” Seventeenth ConferenceAmerican Association for Automotive Medicine,801 Green Bay Road, Lake Bluff, IHinois 60044.

17. J. W. Melvin, J. H. McElhaney, V. L.Roberts and H. D. Portnoy, “Deployable HeadRestraints - A Feasibility Study,” SAE No. 710853,Fifteenth Stapp Car Crash Conference, Society ofAutomotive Engineers, Inc. , Warrendale, Pennsyl-vania 15096, 1971.

18. J. H. McElhaney, R. L. Stalnaker,V. L. Roberts and R. G. Snyder, “Door Crash-worthiness Criteria, ” SAE No. 710864, FifteenthStapp Conference, Society of Automotive Engineers,Inc. , Warrendale, Pennsylvania 15096, 1971.

19. D. M. Severy, H. M. Brink and J. D.Baird, “Passenger Protection from Front-endImpacts , ” SAE No. 690068, International Automo-tive Engineering Congress, Detroit, Michigan,January 1969.

20. D. F. IIuelke, J. C. Marsh, et al,“Injury Causation in Rollover Accidents, ‘I Proceed-ings of Seventeenth Conference of the AmericanAssociation for Automotive Medicine, OklahomaCity, Oklahoma, 1973.

21, P. V. Hight, A. W. Siegel and A. M.Nahum, “Injury Mechanisms in Rollover Collisions, 11SAE No. 720966, Sixteenth Stapp Car Crash Con-ference, Society of Automotive Engineers, Inc. ,Warrendale, Pennsylvania 15096, 1972.