article underride

IMPROVED CRASHWORTHY DESIGNSFOR TRUCK UNDERRIDE GUARDS

Byron BlochAuto Safety DesignPotomac, Maryland USALouis Otto Faber SchmutzlerBiomechanics Engineering Lab.Unicamp State UniversityCampinas, Sao Paulo, Brazil

Presented in October 1998At the 16th InternationalTechnical Conference on theEnhanced Safety of Vehiclesin Windsor, Ontario, Canada

Paper No. 98-S4-O-07

ABSTRACT

When a passenger vehicle collides with a largetruck or trailer rig, this mismatch is furtheraggravated when the passenger vehicle continuesbeneath the rear or side of the taller truck.These are called truck underride crashes… andoften decapitate the upper half of the passengervehicle and its occupants.

In the United States, there is a new federal motorvehicle safety standard requiring a rear underrideprevention guard for newly manufactured trucktrailers beginning in January 1998. The 22-inch maximum permitted height was based on30 mph crash tests, yet contradicts prior NHTSA35-to-40 mph crash test research thatrecommended an 18-to-20 inch height asnecessary to protect smaller vehicles in 40 mphcrashes. The guard strength is minimal, andthe test is only a slow-push on an exemplarguard.

The new regulation also totally ignores the side underride hazard, which accounts for almost halfof the U.S. fatalities in underride accidents eachyear.

Using existing technology, there are manyfeasible designs for rear underride guards andside underride guards that are effective, light-weight, and economical.

Such guards can be utilized on new trucks andtrailers, as well as being capable of being retrofitto existing in-use trucks and trailers. Amongthe explored designs are (A) the use of Bellevillespring-washer stacked pistons, (B) the use ofrigid foam-filled convoluted tube structures, (C)the use of recycled non-metallic synthetics, and(D) cable entrapment platforms.

And what of the requirement for harmonizationof vehicle safety standards, so that all membernations utilize the same underride guardrequirements, and thereby impose a reducedburden for variety among the vehiclemanufacturers?

Can there be a singular international safetystandard for truck underride guards, and if so, itshould be based on the most effectiverequirements, rather than compromised to meetthe least-challenging requirements?

Byron Bloch, Auto Safety Design, Inc.

www.AutoSafetyExpert.com 2

INTRODUCTION:The Truck UnderrideDecapitation Epidemic

When a passenger vehicle crashes into andcontinues beneath.. or underrides… the rearor side of a large truck or trailer, theconsequences to the vehicle’s driver andpassengers are often the extreme ripping into andcrushing of the passenger compartment “survivalspace”, and severe or fatal head injuries or evendecapitation. The prevention of passengercompartment intrusion (PCI) is clearly theprimary purpose of having an underrideprevention guard. Though estimates havevaried over the years, there are likely about 200-to-300 fatalities in underride accidents each yearin the U.S.

There is also the parallel issue of the front ofa large truck crashing over... or overrriding...the lower structures of a passenger vehicle.Thus, there is a need for energy-absorbing andlower-to the-road frontal bumpers and overalldesign considerations to try to reduce the oftenlethal consequences of a massive truck collidinghead-on with a smaller passenger vehicle. (Thefront override issue has been addressed in priorESV papers, and continues as a major focus forneeded safety improvements. This paper willfocus on the truck rear underride and sideunderride issues and designs.)

In the United States, there has recently been anew requirement for an improved rearunderride prevention guard for all newly-manufactured trailers and semi-trailers, as ofJanuary 26th, 1998. The new Federal MotorVehicle Safety Standards are “Rear ImpactGuards”, FMVSS No. 223, and “Rear ImpactProtection”, FMVSS No. 224. The need forsuch underride prevention guards for trucks andtrailers was initially proposed in 1967, somethirty years ago, as one of the initial standardspromulgated by the then-newly- created NationalHighway Safety Bureau (NHSB).

After a laborious and often-delayed thirty-year process from its inception as aproclaimed safety need, until its enactment in1995 and its implementation in 1998, there is

concern that the long gestation period did notgive birth to an optimal safety standard.Admittedly, the process was on-again, off-again,on-again, off-again to such a perplexing extent,that merely having “some standard at last” seemsbetter than continuing that thirty-year delay evenmore. Yet, the new NHTSA regulation hasmany shortcomings:

® The regulation applies only tonew trailers, and does not alsoinclude single-unit trucks, dumptrucks, or other trucks with lethaldesigns.

® The permissible guard heightabove the ground can be up to 22inches, but should be 16 to 18inches to protect smaller vehicles.

® The guard’s strength requirementsare too weak, and were derivedfrom 30 mph crash tests, butshould have been based on 40-plus mph requirements.

® Does not address the side underride hazard, which accountsfor almost 50-percent of allunderride fatalities.

The NHTSA fixation on fatalities does nottake into account the merits of underride guardsin reducing the severity of injuries, or preventingthem completely. Severe brain trauma,extensive facial fractures, and the loss of eyes,are notable injuries that can be prevented withunderride guards.

In many years of investigating car-into-truckcollision accidents and evaluating thecrashworthiness of the involved vehicles, theauthors have noted many truck underrideaccidents in which the ICC rear bumper wasgrossly ineffective in its failure to prevent theintrusion into and crushing of the passengercompartment of the car, pickup, or van. Insome cases, there was no rear or side guard orbumper at all.

In the United States, coal dump trucks andtrash-hauling trucks typically do not have anyrear underride guards or bumpers at all. InBrazil, and in many other nations as well,virtually all trucks are without underride guards,



or there is the pretense of a makeshift rearbumper that is totally ineffective. With orwithout governmental regulations, there is alsoneglect by truck and trailer manufacturers andoperators to voluntarily and compassionatelycorrect the underride hazard by designing andimplementing safer trucks and trailers witheffective underride prevention guards.

The truck industry in many nations, includingthe United States, has well known of theunderride hazard and its toll of death and injury,but has delayed and argued and been indifferentto moving ahead constructively to help solve theunderride hazard problems.

Many European nations, beginning with Swedenin the mid-1970’s, have adopted rear underrideguards. The European Economic Community(EEC) Commission Directive 79/490/EECconcerns rear underrun (underride) protection, andwas enacted in 1979.

With regard to side underrun protection,ECE/TRANS/505 Regulation No. 73 wasenacted in January 1988. While initiallyintended primarily to prevent pedestrians,cyclists, and motorcyclists from getting trappedbeneath the long open sides of large trucks andtrailers, the side underride guards have also been

beneficial to help prevent cars from underriding,especially with angular crashes.

THE ICC REAR BUMPER ISOBSOLETE AND INEFFECTIVE

The 1953 ICC regulation for “Rear EndProtection” has been demonstrated to begrossly ineffective. The vast majority of theICC bumpers at the rear of trucks and trailers aretoo high off the ground (typically in the 24 to 28inch range), are too narrow across the rear of thetruck, and are too weak. These deficiencies ofthe ICC rear bumper have been shown in actualcar-into-truck accidents and crash tests to fail toprevent a passenger car, minivan, compactpickup truck, sport utility vehicle, or van frompenetrating deeply beneath the truck… resultingin passenger compartment intrusion (PCI) thatcauses severe to fatal injuries.

Nothing has prevented a truck or trailermanufacturer from designing rear bumpersthat were safer, and were less than the “shall notexceed”maximums. Many years ago, theycould have designed and installed rear bumpersthat were 18 inches above the ground (notably



below the 30-inch maximum), and full-widthacross the truck’s rear, and that had strengthand energy-absorbing features that optimizedthe prevention of the underride hazard forvehicles that might crash into the rear of thetruck or trailer.

Over the past thirty years, safer rear underrideguard designs have been discussed and described,but they have been largely ignored.

For example, the Truck Trailer ManufacturersAssociation (TTMA) back in 1970 noted that:

“…it is within our competency todesign and and mount on newtrailers an underride guard capableof withstanding the test loadsdescribed in the DOT proposal andat a height of 18 inches above theroad.” “It is possible to providethe dual capability of 50,000(pounds) at the 24-inch height and37,000 (pounds) at the 18-inchheight using the same structure.(See enclosed sketch).”

Yet, in the subsequent 25 years since that 1970proclamation, the TTMA did not recommendednor require that its trailer-manufacturer membersactually implement such safer rear underrideguards.



NHTSA STANDARD SHOULD ALSOAPPLY TO TRUCKS

The new rear underride prevention guardrequirement applies only to trailers and semi-trailers with a gross vehicle weight rating(GVWR) of 10,000 pounds or more. Thestandard does not apply to single-unit trucks,dump trucks, truck tractors, pole trailers, lowchassis trailers, special purpose vehicles, orwheels back vehicles. A “special purposevehicle” is defined as a trailer or semi-trailer thathas work-performing equipment at the lower rearand whose function would be significantlyimpaired by a rear impact guard. The arbitraryweight requirement for excluding trucks andtrailers below 10,000 pounds contradicts the factthat many light-duty and medium-duty and cab-chassis trucks are equipped with truck bodiesthat present the same lethal underride hazard asdo the larger, heavier trailers and semi-trailers.

In its Final Regulatory Analysis of December1995, NHTSA noted that over the past 13years, total car-into-truck rear-end fatalitieshave averaged 421 per year, with 73-percent(308) due to collisions with combination truck-trailers, and the remaining 27-percent (113) dueto collisions with straight trucks (GVWR greaterthan 10,000 lbs.). NHTSA noted that about1.5 times more straight body trucks aremanufactured each year compared to trailers(250,000 straight body trucks versus 162,000trailers).

The fixation on fatalities does not take intoaccount the merits of underride guards inreducing the severity of injuries, or preventingthem completely. Severe brain trauma,extensive facial fractures, and the loss of eyes,are notable injuries that can be prevented withunderride guards.

Because of NHTSA’s abdication of setting asafer standard for straight trucks, it isimportant for the manufacturers and/or their tradeassociation to voluntarily adopt a requirementsimilar to or preferably superior to FMVSS 223and 224. Such a “Recommended Practice”should be issued by the Truck TrailerManufacturers Association (TTMA), theAmerican Trucking Associations (ATA), and the

Truck Body Equipment Association (TBEA),and urged upon its members for immediateimplementation.

Thus, the U.S. now has two different sets ofregulations. For new trailers only, effective in1998, there are FMVSS 223 and 224. But forall other new trucks, the old 1953 ICCregulation is applicable. And for all existingtrucks and trailers, they are also still regulated bythe old ICC regulation, since there is no retrofitrequirement. Thus, there is truly a “double-standard” conflict for new trucks versus newtrailers. Yet, the underride hazard is the same.

If you’re a truck manufacturer, here’s yourdilemma… Let’s assume you manufacturestraight van trucks with a load floor or bedheight at 36 inches, and city delivery van truckswith a bed height of 44 inches. Do youcontinue to use an ICC rear bumper that’spermissibly (albeit unsafely) up to 30 inchesabove the ground, and is inboard about 18 inchesfrom each side ? Or instead, do youincorporate a design that complies with thenewer requirements as specified in FMVSS 223and 224 which are specifically applicable totrailers. The decision should clearly be toadopt a lower, wider, stronger rear underrideguard for all trucks.



Trucks come in all sizes, shapes, andweights… and they all should be designed tominimize the underride hazard if at allpossible. There are coal dump trucks withextensive rear overhangs of about 6 feet, and theyclearly present a lethal underride hazard.

Coal dump trucks and tilt-bed tow trucks andothers can be feasibly equipped with rearunderride guards that automatically pivot andfold rearward beneath the truck body as it tilts inperforming its work function. Shown below isan example of a United States patent for a rearunderride guard that can be retracted upwardwhen the truck dump function is utilized, andthen is returned down to an effective height toserve as an underride prevention guard when thedump truck is traveling on the road.

There are tow trucks with tiltable car-carryingplatforms that project rearward like an ax blade.There are straight body trucks which have framerails or bed heights in the 36-to-48 inch range,presenting an underride hazard virtually identicalto that of a trailer. There are large trucks withtuck-under lift gates that are sloped beneath therear of the truck and can thus accentuate theunderride hazard by “funneling” the car evenlower as it continues beneath the rear of thetruck.

DESIGN FOR CRASHESABOVE 30 MPHAND LOWER GUARD HEIGHT

NHTSA’s most recent crash test program toevaluate the underride situation involved theuse of the subcompact GM Saturn and HondaCivic, and the compact-size Ford Tempo andChevrolet Corsica sedan and Beretta coupe.The car crashed into either a rigid guard or amoderate-strength guard, which were mounted toeither a 1988 Fruehauf 48-foot-long trailer, or aspecially-constructed Rigid Test Fixture that hada ground-to-floor-bottom height of about 49inches. (Refer to “Heavy Truck Rear UnderrideProtection,” VRTC-82-0267, Vehicle Researchand Test Center, East Liberty, Ohio, June 1993,Final Report, DOT HS 808-081.)

The 30 mph crash level for the new NHTSAregulation is grossly inadequate, since thetechnical capability exists to exceed at least a 40-plus mph level. Accident data and caseevaluations indicate that the vast majority oftruck underrides occur in the 30-to-50 mphrange. And prior crash tests programs, such asCornell in 1971 and Dynamic Science in 1980,demonstrated that a 40-plus mph rear underrideguard was feasible, it seems short-sighted of



NHTSA to settle for the unrealistically low levelof 30 mph. Truck and trailer manufacturersshould recognize that the new NHTSA regulation#223 and #224 are only “minimums” that shouldbe significantly exceeded by the installation ofproduction guards with a notably highercapability.

In contrast to this most-recent 30-to-35 mphcrash test series conducted at VRTC in 1993-94, previous NHTSA crash test programs (e.g.,1979-80 at Dynamic Science) for developing andevaluating rear underride prevention guards haveincluded crash tests in the realistic 35-to-40 mphrange… [Note that a 40 mph crash test is about1.8 times more severe than a 30 mph crash test.The energy varies as the square of the velocity…the ratio is (40)2 over (30)2, or 1600/900 = 1.8]

The application of a slowly-applied force tothe underride guard exemplar may notadequately test impact strength. Someunderride guard designs that may be capable ofwithstanding gradually applied loads may failwhen the same amount of force is appliedabruptly. Similarly, the attachment of theguard to the frame structure of the truck or trailermay transfer the applied loads in an actual crashaccident to what may be a weaker frame rail.The applied load requirement of 22,480 lbs. isalso notably below the previously-recommended50,000 lbs. that was derived from crash tests inthe 35-40 mph range, including larger passengervehicles than the Saturn-Civic-Tempo-Corsicarange.

The slowly-applied loads also do notnecessarily account for offest and angularimpacts that occur in real-world accidents, andwhich may tend to overwhelm a vertical supportand cause it to catastrophically fail or break-away… thereby allowing the car to continue todangerously underride beneath the taller truck ortrailer..

The 1971 Cornell crash test program forNHTSA, in its report titled “A Study of Heavy-Vehicle Underride Guards” (SAE 710121),described the twelve car-into-truck crash testswith guard heights of 18 inches and 24 inches.Their conclusion was that an 18 inch guardheight provides protection for the smaller cars.

Small VW Beetles and full-size Fords were usedin most tests.

The 1980 Dynamic Science crash test programfor NHTSA, in its report titled “Development ofCompliance Test for Truck Rear UnderrideProtection” (DOT HS-805-564), noted amongits Recommendations:

“To prevent excessive underride, it isrecommended that the guard heightnot exceed 20 inches at the impactspeeds from 30-40 mph and 22inches below 30 mph to ensureadequate structural engagement ofthe car (engine) with the guard.”

However, when the new FMVSS 223 and 224requirements were issued in the mid-1990’s, theprior recommendations for the 18-inch maximumheight and the 20-inch maximum height wereboth ignored. The new requirement is for a 22-inch maximum height, which is too high inview of the 16-to-20 height of many vehiclebumpers and supporting structures.

THE CRITICAL NEED FOR SIDEUNDERRIDE PROTECTION

The new NHTSA regulation totally ignoresthe need to require side underride preventionguards.

Back in 1968, the National Highway SafetyBureau (which became NHTSA in 1971),funded a study entitled “Development ofStandards for a Heavy Vehicle UnderrideGuard”. The research was conducted byAerospace Research Associates (ARA) ofCalifornia. Various side underride guarddesigns were discussed, including those withenergy-absorbing features. The report notedthat “If a heavy vehicle is struck from the rearor side by a light vehicle, serious injury can beincurred by the occupants of the smaller vehicle.It would appear that equipping such heavyvehicles with rear and side underride guardswould result in a reduction of a number offatalities and the severity of injuries.”



Then in 1970, as the NHSB proceded furtherwith rule-making efforts for rear underrideguards, they noted that further considerationwould be given, after ompleteion of technicalstudies, to underride protection for the sidesof large vehicles. Despite those goodintentions, the side underride efforts wereessentially put in llimbo following the 1971White House directive to cancel or shelve variousthen-pending vehicle safety regulations.

In the 1977 research report “Car-Truck FatalAccidents in Michigan and Texas”, by theHighway Safety Research Institute (HSRI), at theUniversity of Michigan, U.S. Dept. ofCommerce PB-274-111, a study was conductedof car-into-truck and car-into-trailer accidents.As a rough estimate, the researchers noted thatthere would be 261 rear-end underride car-into-truck fatal collisions per year, and 195side underrides per year.

The distribution of points of impact for 181car-truck/trailer fatal crashes were illustratedas shown in this excerpt drawing from the HSRIreport. The report notes not only the largequantity and percentage (almost half) that areside and side-angular crashes, and also notes themajority (65 out of 87) were in the 30-to-50 mphrange

In England and other European nations,side underride guards were implementedbeginning in the early to mid 1980’s to protectmotorcyclists, bicyclists, and pedestrians frombecoming entrapped in the open space along thesides of the trucks and trailers. Discussionswith European colleagues indicate that such sideunderride (or “underrun”) guards have alsodemonstrated effectiveness in helping preventcars from underriding.

Similar to a guard rail along the highway,such side underride guards also can be effectivein helping deflect cars from unsafely underridinginto and beneath the tall sides of trucks andespecially long trailers. When a large tractor-trailer rig makes a lane change on the highway,an adjacent car may not be readily perceived bythe truck driver… and the car gets trapped in thelong-open side of the trailer and crushed by thetrailer’s rear wheels, as well as having thetrailer’s side structures crush into the car’s roof.

Other side underride accidents have occurredwhen a tractor-trailer makes a turn at anintersection or pulls out onto the highway in



front of oncoming traffic. Others occur atnight, for example, when theHeadlights of the tractor create glare to anoncoming driver and thereby camouflages thevisual perception that the tractor’s long trailer isstill diagonally straddling the road ahead.

The use of retro-reflective tape along the sidesand rear of trucks and trailers is exteremelybeneficial in enhancing their “conspicuity” orperception and identification at night and ininclement weather, so that motorists can see andunderstand the nature of the large truck dangerahead, and thereby hopefully avoid the accidentfrom occurring in the first place, or at leastreduce the severity of any collision that mightoccur.

It is imperative for NHTSA to immediatelyfocus on rulemaking for a side underrideprevention safety standard. This would be alogical companion standard to FMVSS 223 and224.

It is interesting to note that NHTSA, back in1970 , noted they soon would be givingconsideration to the subject of underrideprotection for the sides of large trucks andtrailers. Virtually nothing has been done sincethen. There is also a need for a federal safetystandard to address heavy truck frontalaggressivity and front underride prevention.

IMPROVED CRASHWORTHYDESIGNS

Most rear underride guards have been of a simpledesign, with two vertical struts and a singlehorizontal bar. As guard designs have becomestronger and full-width across the rear of thetruck or trailer, additional vertical struts anddiagonal braces and gussets have been added tohelp prevent the guard from bending forward tooeasily, or even breaking a strut completely awayfrom its anchorage.

While the use of energy-absorbing mechanismshas been attempted, few current designs utilizeany such features. Therefore, the typical guardwill begin to yield and bend forward under the

load from a rear-ending car… which can causethe adverse effect of “funneling” the cardownward, compressing the front suspensiondownward, and aggravating the underride hazard.

It is also preferable to utilize rear underride guarddesigns that engage the passenger vehicle at alower height, preferably in the 16-to-18 inchheight above the road surface, so as to moreeffectively engage the front bumper structures,front suspension, and tires. This lowerengagement will help reduce the adverse effect ofthe rear structures of the truck loading essentiallydownward on the car’s sloping hood.

THE BRAZILIAN PLYER GUARD

A novel design for an underride prevention guardwas conceived at the Biomechanics EngineeringLaboratory, at Unicamp State University, inCampinas, Brazil. The particular design isreferred to as the “Plyer Underride Guard”,denoting its relationship to the mechanicalprinciples of a simple pliers tool.

As the passenger vehicle or car engages the low-mounted crossbar, the car becomes entrapped.As the car continues forward, it progressivelydeforms the “net” of steel cables. As thisengagement takes place, it also allows thevehicle's designed-in frontal “crush zone” todeform and absorb the collision forces as well.Thus, the passengers are receiving the dual safetybenefits of the car’s frontal crush zone doing itswork, and also the elimination of the unsafeunderride penetration into the passengercompartment.

The Brazilian Plyer Guard was successfullycrash-tested on April 14, 1998, at the GeneralMotors crash laboratory facilities near the city ofIndaiatuba, Sao Paulo State. The car was aGM Vectra that crashed into the rear of the targettruck at 40 mph in a 50% offset collision.

The Vectra’s front bumper was the first part ofthe car to impact the Plyer Guard’s steel cables,which assured that the Vectra’s designed-inenergy-absorption capabilities, its frontal “crushzone”, was fully employed. The Vectra’swindshield was not touched by any part of the



truck. The front doors could be easily opened,which would thus facilitate the exiting or rescueof the passengers.

In this initial crash test of the Plyer Guard, themain goal of preventing intrusion into thepassenger compartment was fully achieved. Aninitial review of this demonstration crash test ofthe prototype Plyer Guard indicates that it wouldlikely perform well with regard to higher impactspeeds or forces. The project staff willcontinue to optimize the design.

For further details of the Brazilian Plyer GuardProject, including the crash test results, pleaserefer to the internet website as follows:

http://www.cte.unicamp.br./impact

There are other energy absorbing techniques thatcan be readily applied to underride guards.

Belleville Spring Washer Concept:Belleville spring washers are like thin-metal “pieplates” of varying strengths and concave/convexcontours. These “pie plates” can bestrategically stacked within a chamber, so that a

movable piston will react into the stack. Byselecting the strength and contour of these “pieplates”, they can absorb energy progressively sothat smaller cars of lighter weight can be alloweda progressive “ride down” as it crashes into theguard at 30 mph or at 50 mph… since thehigher-speed crash will also engage the stiffer,stronger pie plates. Heavier cars will similarlybe accommodated by the varying energy-absorbing deformability of the differing pieplates that have been stacked within the pistonchamber.

Rigid Foam Filled Structures Concept:The use of high-density rigid polyurethane foaminside of tubular or compartmented structures hasbeen shown to triple the bending strength andcompressive strength of that structure. Thus,the foam-filled design concept enables a light-weight, economical, and efficient technique to beapplied to the design of rear and side underrideguards. For example, the foam-filledstrengthening can be applied within the diagonalstruts that are typically used to brace the verticalmembers of a rear underride guard.



Recycled Non-Metallic SyntheticsThe rubber from used tires is often recycled.The rubber tires are initially shredded andpowdered, and can be mixed with bondingagents to create a moldable basic material. Themolding of underride guard members or rails canbe accomplished in large molds, with inserts ofreinforcements such as wires, cables, orinterwoven fibreglas-type sheets.

The freedom to explore many different and noveldesign for rear underride guards and sideunderride guards should be encouraged. Anearly concept of a dual-level and dual-strengthrear underride guard was shown by the TruckTrailer Manufacturers Association (TTMA) backin 1970. Quinton-Hazell of Englanddemonstrated an energy-absorbing rear underrideguard that utilized hydraulics and pistons.Tube Industries of England demonstrated a novelconcept of inverted tubes to absorb energy (thelarger tube inverted over the smaller tube in amanner somewhat akin to peeling a stocking offof a leg).

CONCLUSION

The truck underride issue will continue to be ofvital concern. The truck underride regulationmust be made applicable to all trucks and trailersthat may present an underride risk, primarily dueto their extended rear overhang profile and sideunderride dangers as well.

We can encourage progress in developing andimplementing side underride guards, and inimproving the rear underride guards that will beinstalled in conformance with the new NHTSAregulation. We can also encourage progress indeveloping and implementing safety measures toalleviate the hazards of heavy truck frontalaggressivity and underrun.

Manufacturers and operators of trucks andtrailers should maximize their efforts andimplement the safest available designs, andnot settle for the minimum levels of compliance.Thus, the continuing epidemic of underrideaccidents will be reduced, many of the underridefatalities and severe injuries will be prevented,

and the industry will reduce its risks and costs oflitigation and liability.

Many nations, such as Brazil, must moveahead expeditiously and adopt regulations torequire that all large trucks and any othervehicles that present an underride hazard, beequipped with effective underride preventionguards.

REFERENCES

1. Rear End Protection , 49 Code of FederalRegulations (CFR), Paragraph 393.86, effectiveJanuary 1, 1953. Established first rear guardrquirements.

2. A mendments to the Initial Federal MotorVehicle Safety Standards , 32 Federal Register14278 (October 14, 1967). Consideration of aFederal Motor Vehicle Safety Standard for RearUnderride Guards for Trucks, Buses, andTrailers. Established the NHTSA Docket No.1-11.

3. “Development of Standards for a HeavyVehicle Underride Guard.”Aerospace Research Associates, Inc. (ARA)Prepared for the National Highway Safety Bureau(NHSB became NHTSA). Dec. 1968.Describes rear and side underride guardrequirements.

4. Rear Underride Protection , 34 FederalRegister 5383, March 19, 1969. Proposed 18-inch maximum height of guard above road, andmovable guards if necessary.

5. Rear Underride Protection , 35 FederalRegister 12956, August 14, 1970. Proposed50,000 pounds static force be applied as test, andconsideration for underride protection for thesides of large trucks.

6. Truck Trailer Manufacturers Association (TTMA), “Rear Underride Protection”, Oct. 21,1970. Noted dual-bumper configuration of 18-inch and 24-inch guards, at 37,000 and 50,000pounds static force capacity respectively.



7. N. DeLays and M. Ryder, “A Study ofHeavy-Vehicle Underride Guards” , CornellAeronautical Laboratory. SAE 710121. 1971.For the National Highway Safety Bureau (NHSBbecame NHTSA).

8. L. Zaremba, J. Wong, C. Moffatt,“Eliminating Automobile OccupantCompartment Penetration in Moderate SpeedTruck Rear Underride Crashes: A Crash TestProgram ”, Insurance Institute for Highway Safety(IIHS).

9. D. Minahan and J. O’Day, “Car-Truck FatalAccidents in Michigan and Texas ,” HighwaySafety Research Institute (HSRI) of theUniversity of Michigan. Oct. 1977.

10. R. Baczynski, N. Johnson, S. Davis,“Development of Compliance Test for TruckRear Underride Protection” , Dynamic Science,Inc. DOT HS-805-564. Sept. 1980. UnderContract to NHTSA.

11. G. Rechnitzer and F.C. Wai, “Fatal andInjury Crashes of Cars into the Rear of Trucks” ,Monash University Accident Research Centre,Australia. May 1991.

12. “Automotive Safety: Are We DoingEnough to Protect America’s Families?” , U. S.Congressional Hearing, Washington, D.C., Dec.4, 1991. Testimony on truck underride hazards,and delay by NHTSA and industry to implementeffective underride prevention guards.

13. ABC News “Primetime Live” televisedreport and transcript of report on truck underridehazards, its regulatory history, accidentexamples, comparison with European adoptionof underride guards, and U.S. industry neglect.January 1992.

14. B. Bloch and E. Wolfe, “Truck UnderrideTragedies”, TRIAL Magazine, Association ofTrial Lawyers of America (ATLA). Feb. 1993.Describes legal basis for liability if manufacturerfails to equip trucks with underride guards.

15. Congressional Report on Truck UnderrideGuards , by NHTSA Office of Vehicle SafetyStandards, Nov. 1993. Included summary ofcar-into-truck crash tests conducted at VRTC.

16. G. Rechnitzer, “Fatal and Injury Crashes ofCars and Other Road Users with the Front andSides of Heavy Vehicles” , Monash UniversityAccident Research Centre, Australia. Feb.1993.

17. “Final Regulatory Evaluation, Rear ImpactGuards, FMVSS No. 223, and Rear ImpactProtection, FMVSS No. 224.” Office ofRegulatory Analysis, NHTSA. Dec. 1995.

18. B. Bloch, “Underride Guards: Is the NewNHTSA Regulation Good Enough?” SAEHeavy Vehicle Underride Protection TOPTECH.April 1997.

19. G. Rechnitzer, “Design Principles forUnderride Guards and Crash Test Results,” Monash University Accident Research Centre,Australia. SAE Heavy Vehicle UnderrideProtection TOPTECH Conference. April 1997.

20. L. Schmutzler, “An Underride GuardDesign for the Brazilian Traffic Environment” ,Unicamp State University, Campinas, Brazil.SAE Heavy Vehicle Underride ProtectionTOPTECH Conference. April 1997

21. J. Tomassoni, “Additional Insights to theUnderride Problem and Concerns.” SAE HeavyVehicle Underride Protection TOPTECHConference. April 1997.

22. F. Hope, “Safety Rear Underride Bar withan Optional Reverse Impact Braking System” .SAE Heavy Vehicle Underride ProtectionTOPTECH. April 1997.



For further information, please refer to theseInternet Websites:

www.AutoSafetyExpert.comIllustrated overview of the history and technology of truck underride, including crash test demonstration synopsis of car-into-truck crashes

with ICC guards and improved guards.Information about contacting Byron Bloch in the United States.

www.cte.unicamp.br/impactInformation about the truck underride efforts in Brazil,

and details of the crash test program of the Brazilian “Plyer Underride Guard”.Information about contacting Luis Schmutzer in Brazil.

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