                                                                                                                           Opinions of the United
1997 Decisions                                                                                                             States Court of Appeals
                                                                                                                              for the Third Circuit


4-22-1997

Surace v. Caterpillar Inc
Precedential or Non-Precedential:

Docket 95-1805




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                 UNITED STATES COURT OF APPEALS
                     FOR THE THIRD CIRCUIT

                           _____________

                            NO. 95-1805
                           _____________

               MICHAEL SURACE; ALICE SURACE, h/w,

                                 Appellants

                                v.

               CATERPILLAR, INC.; CMI CORPORATION,

                                    Appellees

               ___________________________________

         On Appeal From the United States District Court
            For the Eastern District of Pennsylvania
                    D.C. Civ. No. 94-cv-01422
               ___________________________________

                      Argued: July 31, 1996

         Before: BECKER, STAPLETON, Circuit Judges, and
                     WARD, District Judge.*

                     (Filed April 22, 1997)


SOL H. WEISS, ESQUIRE (ARGUED)
KRISTIN WERNER, ESQUIRE
Anapol, Schwartz, Weiss and Cohan
1900 Delancey Place
Philadelphia, PA 19103

Attorneys for Appellants
Michael and Alice Surace


CARY E. HILTGEN, ESQUIRE (ARGUED)
KAREN S. MacLEOD, ESQUIRE
Hiltgen and Brewer
117 Park Avenue Third Floor
Oklahoma City, OK 73102


     *
      Honorable Robert J. Ward, United States District Judge for
the Southern District of New York, sitting by designation.



                                1
JAMES D. GOLKOW, ESQUIRE
Cozen and O'Connor
The Atrium, Third Floor
1900 Market Street
Philadelphia, PA 19103

Attorneys for Appellee
CMI Corporation

                      _____________________

                       OPINION OF THE COURT
                      _____________________


BECKER, Circuit Judge.

     This is a products liability case, Restatement of Torts 2d §

402A, arising out of a construction accident in which the treads

of a huge road profiler machine ran over the foot of plaintiff

Michael Surace.   Surace brought suit against CMI Corporation

("CMI"), the manufacturer of the machine, in the district court

for the Eastern District of Pennsylvania.1    The district court,

concluding that the evidence contained in the summary judgment

record failed to demonstrate that the profiler's risks outweighed

its utility, and also that the profiler presented an obvious risk

which could have been avoided had Surace exercised reasonable

care, granted summary judgment in favor of CMI.    Surace appealed.

     Resolution of the appeal requires us to explore the contours

of the Pennsylvania Supreme Court's decision in Azzarello v.

Black Bros. Co., 480 Pa. 547, 391 A.2d 1020 (1978), which

established that, for purposes of strict liability, whether a

product's condition justifies placing the risk of loss on the

supplier is a threshold question of law for the court to
     1
       Jurisdiction was based upon diversity of citizenship, 28
U.S.C. § 1332.



                                2
determine.2    That Court has also made clear that the threshold

question turns on a social policy determination to be made by the

trial judge.    In post-Azzarello defect cases, the Pennsylvania

Superior Court has determined that this requirement may be

fulfilled by performing a risk-utility analysis, and that the

multi-factor list developed by Dean John Wade may be employed in

doing so. See John Wade, On the Nature of Strict Tort Liability

for Products, 44 Miss. L.J. 825, 837-38 (1973).    Though with some

diffidence, we predict that the Pennsylvania Supreme Court would

adopt that approach.

     The appeal then requires that we apply the risk-utility

factors to our plenary review of the district court's judgment.

When we do so, we find that the risk-utility balance weighs in

favor of the plaintiff.    In particular, we conclude that the

district court erred: (1) in determining that the gravity of the

risk of harm and the ability to eliminate it through use of a

lockout/tagout device, identified by Surace's expert as the

design solution to the defect, were factors weighing in favor of

CMI; (2) in relying on Surace's own conduct to determine that the

profiler was not unreasonably dangerous; and (3) in weighing the

issue of causation as a factor in resolving that question.     We

also conclude that putative alternative grounds for upholding the

summary judgment for CMI do not pass muster.    Accordingly, we

will reverse the grant of summary judgment and remand for further

     2
        The parties agree that Pennsylvania substantive law
governs this diversity action. Nowak By and Through Nowak v.
Faberge, U.S.A., Inc., 32 F.3d 755, 757 (3d Cir. 1994).




                                  3
proceedings consistent with this opinion.

     However, we will affirm the district court's judgment

insofar as it excluded Surace's expert witness Harold Brink from

testifying under Fed. R. Evid. 702.    We agree that Brink lacks

the expertise required to testify regarding the central issue of

design defect in the case -- habituation.     Accordingly, the

district court properly excluded Brink's testimony.
     I.   FACTS AND PROCEDURAL HISTORY

     On the night of September 16, 1992, Surace, an employee of

SJA Construction Company, was working on the New Jersey side of

the Betsy Ross Bridge.   The work crew was using a PR-450 pavement

profiler, which had been manufactured by CMI for Caterpillar,

Inc., to mill rumble strips at the base of the bridge.     The

profiler had been equipped with a conveyor assembly which picked

up and carried debris generated by the profiler to a waiting

receptacle.   However, due to space constraints, the crew was

operating the profiler without the conveyor assembly.

Consequently, the crew was required to level manually the piles

of debris left behind by the profiler.

     On the night of the accident, Surace was working as a left-

side sensor man.   In this position, he was responsible for

signaling the profiler's operator, William Snyder, when to start

and stop the profiler, and in which direction to move it.

Although the profiler was equipped with horns on the side

specifically designed for signaling the operator, Surace was

using hand signals to signal Snyder.     The profiler's design

contained a "blind spot," i.e., the operator's view of the area


                                4
directly behind the machine was obstructed.

     The profiler was equipped with a number of warning devices,

including a sign prominently posted on its rear alerting the crew

to stay at least 25 feet clear of the machine, an automatic back-

up alarm, flashing back-up lights, and a rotating overhead beacon

light which signaled when the profiler was in operation.    These

warning or signaling devices were all in working condition on the

night of the accident.    Surace was wearing earplugs to protect

his ears from the considerable noise created by the machine.

     After the first pass of the profiler, Surace signaled Snyder

to stop.   After moving the profiler forward, Snyder did so.

Surace then noticed a pile of debris in the reverse pathway of

the profiler which the machine had generated.    Surace picked up a

broom or shovel, and, with his back to the machine, began to

level the debris.    While Surace was behind the machine, and

without any signal from Surace, Snyder put the profiler into

reverse. Although the back-up alarms and signals were activated,

Surace neither heard nor saw them, nor did he hear the shouts

from his crew workers to move out of the way.    The profiler

backed into Surace and snared his right foot under the treads.

As a result of the accident, Surace sustained serious injuries,

necessitating the amputation of part of his right foot.

     Surace and his wife Alice (Surace) filed suit against

Caterpillar and CMI alleging negligence and strict liability for

defective design.3   Surace subsequently dropped the negligence

     3
         Alice Surace claimed loss of consortium.




                                 5
claim and, by stipulation of the parties, Caterpillar was

dismissed from the action.    The complaint alleged that the

profiler was defectively designed because its warning devices

were inadequate.    Specifically, Surace alleged that the back-up

alarms were prone to "habituation," a phenomenon by which a

person becomes immune to a particular stimulus through constant

repetition and exposure, and that without a “lockout/tagout”

device, which would prevent the machine from reversing unless

activated by the ground crew, the profiler was unreasonably

dangerous.

     Following a period of discovery, CMI moved in limine to

exclude the testimony of Surace's liability experts, Joseph

Lambert, Harold Brink and Paul Stephens, pursuant to Fed.R.Evid.

702, 703, and 403.     Both Dr. Lambert, a psychologist and

specialist in human factors analysis, and Brink, an

electromechanical engineer, were to testify that the profiler's

warning devices were defective because they were prone to

habituation.     Stephens, a mechanical and safety engineer, was to

testify that the warning devices were inadequate, and that the

failure to equip the machine with additional safety devices

caused the accident.    After conducting an in limine hearing, the

district court denied the motion with respect to Lambert and

Stephens, but granted it with respect to Brink.     Surace v.

Caterpillar, Inc., No. CIV.A.94-1422, 1995 WL 303895 (E.D. Pa.

May 16, 1995).     The court's ruling was predicated largely on the

fact that Brink's opinion hinged on habituation, a field, the

court found, in which Brink lacked experience and for which he


                                  6
relied exclusively on Dr. Lambert for support.

     CMI then moved for summary judgment, arguing, inter alia,

that the profiler was safe for its intended use.      As noted above,

the district court granted summary judgment for CMI on the

grounds that the evidence failed to demonstrate that the

profiler's risks outweighed its utility, and that the profiler

presented an obvious risk which could have been avoided if Surace

had exercised reasonable care.     Surace v. Caterpillar, Inc., No.

CIV.A.94-1422, 1995 WL 495123 (E.D. Pa. Aug. 18, 1995).

     We exercise plenary review in determining the propriety of

summary judgment. Childers v. Joseph, 842 F.2d 689, 693 (3d Cir.

1988).     Summary judgment is proper only if there is no genuine

issue of material fact. Id.      "An issue is `genuine' only if a

reasonable jury, considering the evidence presented, could find

for the non-moving party." Id. at 693-94.
     II.     THE AZZARELLO THRESHOLD ANALYSIS

             A.   Introduction

     Pennsylvania early on adopted the Restatement (Second) of
Torts as the law of strict products liability in Pennsylvania.

Webb v. Zern, 422 Pa. 424, 427, 220 A.2d 853, 854 (Pa. 1966).

Section 402A of the Restatement provides in relevant part:

          (1) One who sells any product in a
     defective condition unreasonably
     dangerous to the user or consumer . . .
     is subject to liability for physical
     harm thereby caused to the ultimate user
     or consumer, or to his property, if (a)
     the seller is engaged in the business of
     selling such a product, and (b) it is
     expected to and does reach the user or
     consumer without substantial change in
     the condition in which it is sold.


                                   7
Restatement (Second) of Torts (1965).   To establish a case under

the strict liability doctrine, a plaintiff must prove that the

product was defective, and that the defect proximately caused the

plaintiff's injuries. Berkebile v. Brantly Helicopter Corp., 462

Pa. 83, 93-94, 337 A.2d 893, 898 (1975).

     In Azzarello v. Black Bros Co., 480 Pa. 547, 558, 391 A.2d

1020, 1026 (1978), the Pennsylvania Supreme Court held that "the

phrases `defective condition' and `unreasonably dangerous' as

used in the Restatement formulation are terms of art invoked when

strict liability is appropriate."   The Court also announced that

the threshold determination as to whether the product's condition

justifies placing the risk of loss on the manufacturer or

supplier is a question of law for the court to resolve. Id., 391

A.2d at 1026.   If the court determines that the product is

defective under the facts as alleged, then the case is submitted

to the jury to determine whether the facts indicate that when the

product left the manufacturer’s control it “lack[ed] any element

necessary to make it safe for its intended use or possess[ed] any

feature that renders it unsafe for the intended use.”   Id. at

559, 391 A.2d at 1027.   The court in Azzarello, however, did not
articulate the standard for determining whether the risk of loss

should be placed on the manufacturer, except to note that it was

a matter of social policy:

     Should an ill-conceived design which
     exposes the user to the risk of harm entitle
     one injured by the product to recover?
     Should adequate warnings of the dangerous
     propensities of an article insulate one who
     suffers injuries from those propensities?
     When does the utility of a product outweigh


                                8
     the unavoidable danger it may pose? These
     are questions of law and their resolution
     depends upon social policy.


Id. at 558, 391 A.2d at 1026; see also Ellen Wertheimer,

Azzarello Agonistes:   Bucking the Strict Products Liability Tide,

66 Temp. L. Rev. 419, 424 (1993) ("Azzarello indisputably failed

to provide courts with guidelines for determining precisely when

and why strict liability should attach."); David G. Owen,

Rethinking the Policies of Strict Products Liability, 33 Vand. L.

Rev. 681, 686-87 (1980) (Azzarello "did very little to help

clarify the meaning of defectiveness and its proper standards of

measure") (“the [Azzarello] court nowhere explicitly connects the

test of liability chosen -- ‘unsafe for the intended use’ -- to

even the weak policies that it does set forth”).

     B.   Risk-Utility Analysis

     Because we are sitting in diversity, we are, of course,

required to the extent necessary to our decision to predict how

the Pennsylvania Supreme Court would apply the Azzarello

standard.   In doing so, we give "`due regard' to the decisions of

Pennsylvania's intermediate appellate courts as `indicia of how

the state's highest court would decide a matter.'" Nowak, 32 F.3d
at 758 (quoting Ciccarelli v. Carey Canadian Mines, Ltd., 757

F.2d 548, 553 n.3 (3d Cir. 1985)).

     Absent further guidance from the Supreme Court, the

Pennsylvania Superior Court has determined that in performing the

social policy analysis, a court must play a dual role, acting as

both a "social philosopher" and a "risk-utility economic

analyst." Fitzpatrick v. Madonna, 424 Pa. Super. 473, 476, 623


                                  9
A.2d 322, 324 (1993); Carrecter v. Colson Equip. Co., 346 Pa.

Super. 95, 101 n.7, 499 A.2d 326, 330 n.7 (1985).   In doing so,

courts, including the district court in the case sub judice,

engage in a risk-utility analysis, weighing a product's harms

against its social utility. Smialek v. Chrysler Motors Corp., 290

Pa. Super. 496, 502, 434 A.2d 1253, 1256 (Pa. Super. Ct. 1981)

("the question of whether a product is defective reaches the jury

only after the court has weighed the relative risks and utility

of the product"); see also Burch v. Sears, Roebuck & Co., 320 Pa.

Super. 444, 450-51, 467 A.2d 615, 618 (1983).

     The Superior Court's approach in this respect seems

consistent with the tenor of the Pennsylvania Supreme Court's §

402A jurisprudence.   Indeed, in Azzarello, the Supreme Court

indicated that a risk-utility inquiry may be appropriate in

performing the social policy analysis. Azzarello, 480 Pa. at 558,

391 A.2d at 1026 (suggesting that a court inquire as to whether

“the utility of a product outweigh[s] the unavoidable danger it

may pose").   Furthermore, Dean John Wade's article setting forth

the risk-utility analysis was cited favorably throughout the

Azzarello decision. Id. at 556 n.8,10, 557-58, 391 A.2d at 1025
n.8,10, 1026.   That fact, coupled with its long hegemony in

Pennsylvania -- risk-utility analysis has been used by state and

federal trial courts since at least 1985 without comment by the

Pennsylvania Supreme Court -- satisfies us that the Supreme Court

would adopt it.

     To be sure, the Pennsylvania Supreme Court has rejected the

risk-utility approach to defining design defect in favor of the


                                10
"intended use" approach.   Lewis v. Coffing Hoist Div., Duff-

Norton Co., 515 Pa. 334, 340, 528 A.2d 590, 593 (1987), cited in

Habecker v. Clark Equip. Co., 942 F.2d 210, 213 n.2 (3d Cir.

1991).4   And, the Pennsylvania Superior Court has relied on Lewis

in rejecting actions which are based on a risk-utility theory of

liability.5   But the courts, including this one, have not

interpreted Lewis as supplanting application of the risk-utility

analysis as part of the threshold social policy inquiry.     See
     4
       In Lewis, the Supreme Court acknowledged various
approaches to determining whether a product is defectively
designed. The court noted that under a "consumer expectations"
approach, adopted by the California Supreme Court in Barker v.
Lull Engineering Co., 20 Cal. 3d 413, 143 Cal. Rptr. 225, 573
P.2d 443 (1978), a product is deemed defective in design "if it
failed to perform as safely as an ordinary consumer would expect
when used in an intended or reasonably foreseeable manner." 515
Pa. at 528 A.2d at 593. The Lewis court took cognizance of the
risk-utility approach, under which a product design is defective
where "on balance, the benefits of the challenged feature
outweigh the risk of danger inherent in such design," id. 528
A.2d at 593, but went on to state that the Azzarello court "sets
forth yet another approach" to determining design defects -- the
intended use approach. Id., 528 A.2d at 593 (citing Azzarello,
480 Pa. at 559, 391 A.2d at 1027).
     5
      In Hite v. R.J. Reynolds Tobacco Co., 396 Pa. Super. 82,
90-91, 578 A.2d 417 (1990), the plaintiff brought a strict
liability suit against a cigarette manufacturer. Rather than
allege a specific defect, the plaintiff argued that the product
was defective because the risks of cigarettes are outweighed by
their social utility. The Superior Court, noting that the
Supreme Court in Lewis had declined to embrace the risk-utility
approach to defining design defect, rejected the plaintiff's
theory. Id. at 91, 578 A.2d at 421; accord Miller v. Brown &
Williamson Tobacco Corp., 679 F. Supp. 485, 489 (E.D. Pa. 1988),
aff’d, 856 F.2d 184 (3d Cir. 1988). Likewise, in Dauphin Deposit
Bank & Trust Co. v. Toyota Motor Corp., 408 Pa. Super. 256, 265,
596 A.2d 845 (1991), a panel of the Superior Court rejected the
plaintiff's theory that strict liability should be imposed
against an alcohol manufacturer solely because the risks
associated with alcoholic consumption outweigh their utility.
The Superior Court panel suggested that the risk-utility theory
of liability was not a cognizable approach to defining defect
under Pennsylvania strict liability law. Id., 596 A.2d 849.



                                11
Motter v. Everest & Jennings, Inc., 883 F.2d 1223, 1227 (3d Cir.

1989); Shetterly v. Crown Controls Corp., 719 F. Supp. 385, 399

(W.D. Pa. 1989), aff'd, 898 F.2d 142 (3d Cir. 1990); Marshall v.

Philadelphia Tramrail Co., 426 Pa. Super. 156, 165, 626 A.2d 620,

625 (1993).6   That result is consistent with the Pennsylvania

Supreme Court’s discussion in Lewis, which confirms, throughout,

its “harmony” with Azzarello.

     At all events, Lewis does not purport to cut back on

Azzarello, and the discussion in Lewis that seems to have caused

some confusion is background and arguably dicta; the question for
     6
      In Griggs v. BIC Corp., 786 F. Supp. 1203 (M.D. Pa. 1992),
the plaintiffs sought to have strict liability imposed, not
because the product, a disposable butane lighter, was unsafe for
its intended use, but because it was unreasonably dangerous to
foreseeable users, i.e., children. The plaintiffs advocated use
of the risk-utility approach to design defect, rather than the
"intended use" approach, arguing that because it was foreseeable
that children would misuse the lighters and it was feasible to
design child-proof lighters, on balance, the product was
defective. The district court, citing Hite and Dauphin, noted
that the Pennsylvania courts have rejected the risk-utility
approach to design defect cases. Id. at 1206-07. The court,
however, correctly distinguished between the use of risk-utility
as an approach to defining defect and as a method for evaluating
a product's 'unreasonable dangerousness' under the rubric of
strict products liability. Id. at 1207 n.4.
          On appeal, a panel of this Court relied on the Supreme
Court's decision in Lewis in affirming the district court on this
issue. Griggs v. BIC Corp., 981 F.2d 1429, 1433 n.6 (3d Cir.
1992). In light of the underlying facts of the case, we read the
panel's decision in Griggs as rejecting the argument that the
risk-utility approach to defining defect should be used instead
of the "intended use" approach; however, to the extent that the
panel's decision can be read as rejecting outright the use of a
risk-utility analysis as a part of the threshold determination,
it is contrary to our decision in Motter, supra, which,
subsequent to the Lewis decision, sanctioned this approach, and,
therefore, carries no precedential weight. See O. Hommel Co. v.
Ferro, 659 F.2d 340, 354 (3d Cir. 1981) ("[A] panel of this court
cannot overrule a prior panel precedent. . . . To the extent that
[the later case] is inconsistent with [the earlier case, the
later case] must be deemed without effect." (citation omitted)).



                                12
decision in Lewis was whether evidence of industry standards was

admissible in a design case.    We do not minimize the background

discussion, and observe that it seems quite correct (as well as

consistent with Azzarello, for it establishes no more than that

the known hazards of products such as cigarettes or alcohol, see

supra n. 6 or, presumably, cigarette lighters, see supra n. 7, do

not automatically render their manufacturers or sellers liable on

the theory that their utility is outweighed by the risks of their

usage).   Rather, Lewis established only that, after the threshold

Azzarello determination by the court, the jury must determine

whether, under the facts, the product, at the time it left the

defendant’s control, lacked any element necessary to make it safe

for its intended use or contained any condition that made it

unsafe for use.      See Pennsylvania Suggested Standard Civil Jury

Instructions § 8.02 (Definition of “Defect”).

     In sum, our prediction that Pennsylvania would employ a

risk-utility analysis in making the threshold Azzarello

determination is not inconsistent with Lewis, and we affirm the

district court's use of a risk-utility analysis in determining

whether the risk of loss should be placed on CMI.

     We regret that the Supreme Court has not yet spoken

definitively on the matter of risk-utility analysis or its

component factors.    Since it is almost twenty years since

Azzarello, we hope that the Court will speak definitively soon.
Unfortunately, we do not have a certification procedure, see

generally Hakimoglu v. Trump Taj Mahal Assoc., 70 F.3d 291, 302-
04 (3d Cir. 1996) (Becker, J., dissenting), through which we



                                  13
could ask that court (in an appropriate case) for an early

resolution of the question that is so critically important in

many of the large number of diversity cases that are brought in

the federal district courts of the Third Circuit.   We do not

suggest that this is that case, because the outcome does not

depend on the answer.   If the Pennsylvania Court should adopt a

certification procedure, we must be careful to be judicious,

indeed sparing, in our use of it even though any such procedure

would necessarily give that court the absolute right to decline

certification in any case.   To act otherwise would be to strain

the delicate federal-state relationship which needs to be

nurtured, not impaired.

     C.   The Wade Factors

     Absent guidance from the state Supreme Court, the Superior

Court has also identified factors that may be considered in

making the threshold risk-utility analysis, including the

following list developed by Dean John Wade:


(1) The usefulness and desirability of the product -- its

     utility to the user and to the public as a whole; (2)

     The safety aspects of the product -- the likelihood

     that it will cause injury, and the probable seriousness

     of the injury; (3) The availability of a substitute

     product which would meet the same need and not be as

     unsafe; (4) The manufacturer's ability to eliminate the

     unsafe character of the product without impairing its

     usefulness or making it too expensive to maintain its



                                14
     utility; (5) The user's ability to avoid danger by the

     exercise of care in the use of the product; (6) The

     user's anticipated awareness of the dangers inherent in

     the product and their avoidability, because of general

     public knowledge of the obvious condition of the

     product, or of the existence of suitable warnings or

     instruction; and (7) The feasibility, on the part of

     the manufacturer, of spreading the loss of [sic]

     setting the price of the product or carrying liability

     insurance.

Dambacher v. Mallis, 336 Pa. Super. 22, 50 n.5, 485 A.2d 408, 423

 n.5 (1984) (citing Wade, supra, 44 Miss. L.J. at 837-38); see

also Fitzpatrick, 424 Pa. Super. at 476-77, 623 A.2d at 324

(citing Wade factors); Phillip v. A.P. Green Refractories Co.,

428 Pa. Super. 167, 180, 630 A.2d 874, 881 (1993); Riley v.

Warren Mfg., Inc., 688 A.2d 221, 225 (Pa. Super. Ct. 1997).    The

district court applied these factors and determined that the

profiler was not defective and, therefore, that the risk of loss

should not be placed on CMI.   We endorse the district court's

methodology.   Application of the Wade factors also seems

consistent with the tenor of the Pennsylvania Supreme Court's

jurisprudence, and we believe that the Supreme Court would find

it acceptable and would probably follow it, though there are

problems of construction, particularly with respect to factor 5,

discussed infra.7
     7
        We note that in addition to the Wade factors, the
Pennsylvania Superior Court has suggested another set of factors,
developed by the California Supreme Court, which may be used in


                                15
     On appeal Surace submits that CMI should have altered the

design of the profiler by equipping it with additional safeguards

such as a transmission lock (a "lockout/tagout device").8   We

turn our attention to the various Wade factors.
          1. Gravity of the Risk of Harm and Ability
              to Eliminate It Through Use of the
              Lockout/Tagout Device
              (Wade Factors Two and Four)


     The gravamen of Surace's argument is that the profiler was


performing the risk-utility analysis:

          (1) The gravity of the danger posed by
          the challenged design; (2) the
          likelihood that such danger would occur;
          (3) the mechanical feasibility of a
          safer design; (4) the financial cost of
          a safer design; and (5) the adverse
          consequences to the product that would
          result from a safer design.

See Dambacher, 336 Pa. Super. at 50 n.5, 485 A.2d at 423 n.5
(citing Barker, 20 Cal. 3d at 431, 143 Cal. Rptr. at 237, 573
P.2d at 455). The Barker factors also reflect the Pennsylvania
Supreme Court's approach to strict liability. We focus on the
Wade factors which are more widely accepted (in Pennsylvania and
elsewhere) and are more comprehensive, including the Barker
factors within their compass. At all events, it is the Wade
factors that the district court applied, albeit incorrectly, and
hence, we limit our discussion to those factors.
     8
       In the district court, Surace also argued that CMI should
have provided the operator an unobstructed view of ground
personnel, or added a rear guard, described as a cow catcher. At
oral argument, Surace indicated that he was abandoning the cow
catcher design and pursuing the lockout/tagout device as the
"main [but not exclusive] thrust" of his argument. However, his
brief is devoid of argument with respect to the district court's
disposition under Azzarello of the alternative proffered designs,
including the need for variable alarms. Accordingly, appellate
review of these alternative arguments has been waived. United
States v. Voigt, 89 F.3d 1050, 1064 n.4 (3d Cir.) (failure to
raise a theory as an issue on appeal constitutes a waiver), cert.
denied, -- U.S. --, 117 S. Ct. 623, 136 L.Ed.2d 546 (1996). This
case does not present extraordinary circumstances that might
warrant review of any unpreserved issues. Id.



                               16
defective and unreasonably dangerous because of the combination

of the "blind spot" and the phenomenon of habituation, and that

this defect could have been eliminated through the use of a

lockout/tagout device, which would prevent the operator from

engaging the profiler in reverse until a switch is activated by

ground personnel.   The device would incorporate the safety

engineering technique of lockout/tagout, a concept which,

according to Surace's expert, although not currently in use for

this specific purpose, has been proven and tested, particularly

in the area of machine maintenance.   The Occupational Safety and

Health Administration has defined a lockout device as one that

"utilizes a positive means such as a lock . . . to hold an energy

isolating device in a safe position and prevent the energizing of

a machine or equipment." See 29 C.F.R. § 1910.147(b)(1996).    In

this case, it would prevent the operator "from inadvertently

releasing the energy" and reversing the profiler without

affirmative action by the ground crew.

     Surace contends that, in rejecting this theory, the district

court failed to view the evidence in the light most favorable to

him. Barker v. Deere Co., 60 F.3d 158, 166 (3d Cir. 1995) (when
performing Azzarello analysis, a court must view the evidence in

the light most favorable to the plaintiff) (citing Burch, 320 Pa.

Super. at 450-51, 467 A.2d at 618-19).9   In determining that the
     9
        We note that this conclusion is problematic. This is
because the risk-utility calculus (or indeed any mode of making
the social policy determination required by Azzarello) is a legal
determination which should probably not be predicated upon a
weighted view of the evidence. The Pennsylvania Supreme Court
might want to revisit this aspect of the matter if and when it
definitively comes to grips with the issues we have identified in


                                17
profiler did not pose a grave risk of harm as currently designed

(we view this as an application of Wade factor two), the district

court primarily relied on its conclusion that Dr. Lambert had not

stated in his report that Surace had in fact become habituated to

the alarm, but had merely opined that the alarm was prone to

habituation.    The court also based its determination on its

conclusion that Lambert had neither tested Surace for habituation

nor explained in his report how, when Surace was injured shortly

after the first pass of the profiler, he could have become

habituated to the alarm, since habituation requires constant or

repeated exposure.

     Lambert's report, which provided a human factors analysis of

the accident, was based on collected accident reports, the

results of noise measurements taken of the profiler, and human

factors literature.   In his deposition testimony, Lambert

admitted that, although it was feasible, he had not tested Surace

to determine whether or not he was habituated.    He further opined

that, "because Mr. Surace had been around this piece of equipment

for such a long period of time, for months, that he habituated to

this alert.    And that habituation became a long-term habituation

that could carry from day to day."    Thus, although he did not

note it in his report, Lambert did conclude that Surace had

become habituated, and he further explained how Surace could be

habituated on the profiler's first pass of the evening.      In view

of the fact that Lambert's testimony was before the court as part

this opinion.




                                 18
of the summary judgment record, the district court was not at

liberty to ignore it.    Moreover, because the habituation issue

will go to the jury in its determination as to whether the

profiler was unsafe for its intended use, the district court

could not resolve any dispute over the issue at that stage.

     We underscore that, in the Azzarello context, the case would

not become one for the jury if the district court were able to

hold as a matter of law that the risk-utility balance so favored

the manufacturer that the profiler could not be deemed

unreasonably dangerous. See Barker, 60 F.3d at 161.   Given the

considerations we have just articulated, and the fact that the

profiler will from time to time cause injury and, if so, the

injury will be serious given the immensity and huge weight of the

machine, we do not believe that the court could properly hold, on

account of disputed habituation evidence, that there was not a

sufficiently grave risk of harm from the profiler to weigh in

favor of Surace on the risk-utility analysis (Wade factor two).

     Applying the fourth Wade factor, the district court rejected

Surace's contention that, because of the phenomenon of

habituation, the profiler should have been equipped with a

lockout/tagout device.   As proffered, the lockout/tagout device

would prevent the operator from engaging the profiler in reverse

until a ground worker activated a switch.   As currently designed,

the profiler relies on horns located on the sides of the machine

which must be activated by ground personnel, who, after visual

inspection, signal the operator that it is clear to reverse.      It

is undisputed that on the night of the accident, Surace was using


                                 19
hand signals rather than these horns to signal the operator and

that the operator put the profiler in reverse without waiting for

a signal from Surace.    The district court concluded that there

was no evidence that the profiler was defective without a

lockout/tagout device.   It noted that Surace's expert, Stephens,

was unaware of any profiler with this device, and concluded that

he could not therefore attest to the technological or economic

feasibility of such a device.

     In his report, Stephens explained that the machine was

inherently dangerous without a lockout/tagout device because of

its "blind spot," coupled with the fact that crew members were

required to work in close proximity to it. Stephen's Report at 3

("severity of hazard and frequency of laborer exposure to the

hazard dictated that [such a device] be provided on the

machine").    Stephens further stated that the lockout/tagout

device was both technically and economically feasible.    In

concluding that he had not shown that the device was mechanically

feasible, the district court emphasized that Stephens did not

know of any currently designed construction machinery that uses

the device.    That conclusion, however, runs afoul of our decision

in Barker, where we held that "a district court, during its

threshold determination, may [not] consider the nonexistence of a

safety device as evidence of its nonfeasibility." Barker, 60 F.3d

at 166-167; see also Habecker v. Clark Equipment Co., 36 F.3d

278, 286 (3d Cir. 1994) ("The fact that the [safety device] did

not exist . . . does not mean that it was incapable of being

placed on the [profiler] if it did in fact exist.").


                                 20
     Although Stephens admitted that the device was not currently

employed by construction machinery for this purpose, he

repeatedly testified that such a device was used in other

applications, that the concept had been tested and proven on

machines comparable to the profiler, and that it could be applied

to work for this specific purpose.    We have previously held that

expert testimony alone may be sufficient, for purposes of summary

judgment, to demonstrate feasibility, see Hollinger v. Wagner

Mining Equip. Co., 667 F.2d 402, 409-10 (3d Cir. 1981), and

further held that, while "a clear and concise diagram or verbal

picture of the type of device" would be helpful, it is not

required to defeat a motion for summary judgment.10 Id. at 410.

While it would have been preferable for Stephens to have

proffered design drawings or developed a prototype of the device,

his testimony was sufficient for purposes of the threshold risk-

utility calculus to make a showing of the feasibility of a

lockout/tagout device, at least in the absence of a

countervailing showing by CMI.   We note that, in accordance with
     10
        In Hollinger, a panel of this Court noted that the
district court had analyzed the question of summary judgment
“under the traditional standard of sufficiency of the evidence to
present a jury question,” and not as threshold matter under
Azzarello. Hollinger, 667 F.2d at 410 n.11. However, in the
context in which the case was decided, the panel did not pass on
the propriety of the district court's action. Id. We have
previously held that the threshold legal determination under
Azzarello regarding the unreasonable dangerousness of the product
is properly made in the context of summary judgment or directed
verdict. Nowak, 32 F.3d at 758. However, the question for the
court to determine is whether the evidence is sufficient, for
purposes of the threshold risk-utility analysis, to conclude as a
matter of law that the product was not unreasonably dangerous,
not whether the evidence creates a genuine issue of fact for the
jury.



                                 21
Azzarello, the technical feasibility issue will go to the jury in

determining whether the lockout/tagout device was an element

necessary to make the profiler safe for its intended use.

Azzarello, 480 Pa. at 588, 391 A.2d at 1026.11

     Finally, the district court concluded that there was

insufficient evidence from which to determine whether the

profiler would be safer if equipped with a lockout/tagout device.

 Emphasizing that, as currently designed, the profiler relies on

the crew to signal the operator that it is safe to reverse, the

court concluded that the lockout/tagout device performs the same

function and, because it relies on crew members to activate the

device, "provides no assurance that human error as occurred here"

would not cause another accident.     Surace, 1995 WL 495123, at *7.

 However, unlike the current design, the lockout/tagout device

would prevent the machine from going in reverse without

affirmative action by the ground crew which, unlike the operator,

have an unobstructed view of the reverse path of the machine.

Stephens acknowledged that he could not state with a reasonable

degree of scientific certainty that the device could prevent the

type of accident from occurring; however, he did attest that it

would "cut the risk significantly."

     In sum, while such a design could not entirely eliminate the

possibility that after the machine was put into motion a crew

     11
        Stephens merely stated, without explanation, that the
lockout/tagout device was economically feasible. However,
although we conclude that his evidence was marginal with respect
to this Wade factor, the totality of the factors relevant here
would require the same result.



                               22
worker could walk into its pathway, it would obviously render the

machine safer.   This conclusion is “in sync” with the

Pennsylvania courts' approach to determining whether the risk of

loss should be placed on the manufacturer.    The court must

balance "the utility of the product against the seriousness and

likelihood of the injury and the availability of precautions

that, though not foolproof, might prevent the injury." Burch, 320

Pa. Super. at 450, 467 A.2d at 618 (emphasis added).     Although a

conclusion that the profiler would be made safer if equipped with

a lockout/tagout device does not require a finding by the court,

or even the jury, that the profiler is defective, viewing the

evidence in the light most favorable to Surace we conclude that

the district court could not, on this basis, decide that the

profiler was not unreasonably dangerous.

     Couching this discussion in terms of the Wade factors, since

it appears that the lockout/tagout device could eliminate the

unsafe character of the product and since it does not appear that

the lockout/tagout device would be expensive or would otherwise

impair the utility of the profiler, the second and fourth Wade

factors weigh in favor of Surace.    Therefore, unless other

factors control the balance, the case must be submitted to the

jury.

          2.   Consideration of Surace's Conduct and
                the Fifth Wade Factor


     In finding that the profiler's risks were not outweighed by

its utility, the court concluded that the accident could likely

have been avoided had Surace exercised due care.     Specifically,


                                23
the court found that because Surace was an experienced

construction worker, fully aware of the dangers posed by the

profiler, his conduct in wearing earplugs and turning his back to

the machine while standing in its pathway was both careless and a

cause of the accident.    The court observed that "[i]t would be

unjust to burden CMI with liability in a situation where there is

clear evidence that Mr. Surace's own lack of care played a role

in bringing about the accident." Surace, 1995 WL 495123, at *9.

On appeal, Surace argues that the district court erred in

considering his conduct as part of the Azzarello threshold

analysis.    He submits that such a consideration impermissibly

interjects concepts of negligence into a strict liability case.

     Pennsylvania courts generally bar consideration of

contributory negligence in strict liability actions. See Kimco

Dev. Corp. v. Michael D's Carpet, 536 Pa. 1, 8, 637 A.2d 603, 606

(1993) (rejecting comparative negligence as a defense in a strict

liability case); see also Dillinger v. Caterpillar, Inc., 959

F.2d 430 (3d Cir. 1992).12   Indeed, the Pennsylvania Supreme
        12
            In Dillinger, after a thorough analysis of
Pennsylvania strict liability law, we concluded that the
"[Pennsylvania] Supreme Court has unequivocally excluded
negligence concepts from product liability cases" and, therefore,
the district court had erred in ruling that evidence of the
plaintiff’s contributory negligence was admissible to rebut
causation. 959 F.2d at 443, 444. Our opinion in Dillinger has,
however, not put to rest all questions relating to the manner in
which a plaintiff's negligence may be considered in a § 402A
case. Compare Kramer v. Raymond Corp., 840 F. Supp. 333, 335
(E.D. Pa. 1993) (relying on Dillinger for the proposition that
evidence of a plaintiff's conduct is admissible only to show that
the plaintiff has assumed the risk or misused the product), with
Kern v. Nissan Indus. Equip. Co., 801 F.Supp. 1438, 1441 (M.D.
Pa. 1992) (evidence of negligence is admissible to rebut
causation where the plaintiff's conduct triggered events
resulting in injury), and Kolesar v. Navistar Int'l Transp.


                                 24
Court eschews the use of negligence concepts in a strict

liability case. See Lewis, 515 Pa. at 341, 528 A.2d at 593

("negligence concepts have no place in a case based on strict

liability").   The theoretical basis for this approach is that

strict liability focuses on the condition of the product; it is

irrelevant that the injury was the result of the manufacturer's

or consumer's negligence. Kimco, 536 Pa. at 7-8, 637 A.2d at 605-

06; Lewis, 515 Pa. at 341, 528 A.2d at 593.

     An individual plaintiff's failure to exercise care in the

use of a product is not relevant to whether the product is

unreasonably dangerous in the first place. See Fleck v. KDI

Sylvan Pools Inc., 981 F.2d 107, 119 (3d Cir. 1992) ("product

liability laws . . . encourage manufacturers to make safe

products even for the careless and unreasonable consumer");

Berkebile, 462 Pa. at 95 n.6, 100, 337 A.2d at 899 n.6, 902

(1975) (rejecting even the "reasonable" consumer standard for the

"ordinary" consumer); see also William J. McNichols, The

Relevance of the Plaintiff's Misconduct in Strict Tort Products

Liability, the Advent of Comparative Responsibility, and the
Proposed Restatement (Third) of Torts, 47 Okla. L.Rev. 201, 207

(1994) ("unreasonably dangerous" determination requires objective

inquiry into the "class of ordinary purchasers").   Therefore, the

district court's consideration of Surace's conduct runs afoul of

Pennsylvania § 402A jurisprudence.13

Corp., 815 F.Supp. 818, 822 (M.D. Pa. 1992) (same), aff’d, 995
F.2d 217 (3d Cir. 1993).
        13
            We note further that, even assuming arguendo, that
consideration of Surace's conduct had been appropriate under


                                25
     The district court believed that by endorsing the Wade

factors, specifically, the fifth factor, (the user’s ability to

avoid danger by the exercise of care in the use of the product),

the Pennsylvania Superior Court has expressly sanctioned

consideration of a product user's conduct in failing to exercise

care as an appropriate factor in performing the threshold

analysis.    Although the Pennsylvania Supreme Court has not

sanctioned use of the Wade factors, we have predicted that it

will. See supra at 14.    That prediction nonetheless admits of the

possibility that the court will adopt some but not all of the

Wade factors.    We note that at least one justice has commented on

the limitations of these factors in one respect. See Sherk v.

Daisy-Heddon, 498 Pa. 594, 625-26, 450 A.2d 615, 631-32 (1982)

(Larsen, J., dissenting) (noting that use of these factors as the

standard for determining whether a product is defective fails in

its "attempt to maintain a distance from negligence concepts”).

     In applying the fifth Wade factor, the district court looked

to Surace's conduct, rather than to an ordinary product user's

conduct.    We believe that it erred in so doing.   The Wade factors

set forth an objective test to determine whether a product is
Azzarello, the district court erred in its application of the
facts. The district court first suggested that Surace's use of
earplugs was careless. However, SJA required its crew to wear
earplugs. Moreover, on appeal, CMI concedes that federal
regulations require the use of protective ear gear at the level
at which the profiler's alarms sounded (100 db). CMI Br. at 22.
Furthermore, although it was undisputed that Surace had turned
his back to the machine, it was also clear that the operator
moved the machine without being signaled, and that he had never
done this in the past. Surace Dep. at 150; Fisher Dep. at 44.
Therefore, a reasonable jury could infer that Surace's actions
were not careless.



                                 26
defective; the "user" referred to in the factors is the ordinary

consumer who purchases or uses the product. Williams v. Briggs

Co., 62 F.3d 703, 707 (5th Cir. 1995) (applying Mississippi law

and noting that the fifth Wade factor focuses on "an ordinary

person's ability to avoid the danger by exercising care"); Riley

v. Becton Dickinson Vascular Access, Inc., 913 F. Supp. 879, 889-

90 (E.D. Pa. 1995)("we are concerned with the ability of the

[product's users], in general, to avoid the risks inherent in the

product, not with the particular circumstances of [a] plaintiff's

accident" (emphasis added)); Johansen v. Makita U.S.A., Inc., 128

N.J. 86, 100-01, 607 A.2d 637, 645 (1992) ("risk-utility analysis

is an objective test that focuses on the product" and the fifth

Wade factor requires consideration of "the extent to which the

hypothetical `average user' of the product -- not the plaintiff -

- could avoid injury through the use of due care."); see

generally Wade, supra, 44 Miss. L.J. at 847 ("strict liability

. . . is imposed on an objective basis").

     The proper focus in applying the fifth Wade factor then is

an objective inquiry into whether the class of ordinary

purchasers of the product could avoid injury through the exercise

of care in use of the product, not whether this particular

plaintiff could have avoided this particular injury.   Put

differently, the user's ability to avoid injury by the exercise

of care in the use of the product appears to be a design factor

that may justify a more or less exacting design depending on the

facts, but it is, in any case, not a vehicle for injecting a

plaintiff's (alleged) failure to exercise due care into the case.


                               27
 Thus, the district court misapplied this factor.

     We acknowledge that, notwithstanding the foregoing

discussion, it is unclear whether the Pennsylvania Supreme Court

would endorse even an objective application of the fifth Wade

factor in performing the Azzarello threshold analysis.     The court

has held that the existence of due care in strict liability cases

is irrelevant, both with respect to the supplier and the

consumer. Berkebile, 462 Pa. at 94, 337 A.2d at 899.   Although it

may appear that in doing so, that court has implicitly rejected

the fifth Wade factor, its concern is with divorcing negligence

concepts from strict liability proceedings;14 we do not believe

that the inquiry suggested by the fifth Wade factor injects

negligence into the action or diverts the focus away from the

condition of the product, but rather it informs the decision as

to whether the product, as designed, is not reasonably safe when

used as intended.

     As Dean Wade explained in his seminal article enunciating

the factors, the focus of the inquiry is on the product:

Suppose that a consumer buys and wears shoes that are too
     little or tires that are too large for his automobile,
     or that he uses the product without following
     instructions. If he is injured as a result and brings
     14
      See Berkebile, 462 Pa. at 97, 337 A.2d at 900 (holding
trial court erred in instructing on manufacturer's
foreseeability, as "[t]o require foreseeability is to require the
manufacturer to use due care in preparing his product. In strict
liability, the manufacturer is liable even if he has exercised
all due care."); see also Brandimarti v. Caterpillar Tractor Co.,
364 Pa. Super. 26, 33, 527 A.2d 134, 138 (1987) (where trial
court had instructed jury that plaintiff's "misuse", "abuse", or
"abnormal use" of the product was a defense to a strict liability
claim, the court cautioned that, on remand, the introduction of
the element of due care was not an issue).



                               28
     suit, the problem may be posed in terms of whether he
     was at fault and whether his fault should bar recovery
     in an action based on strict liability. The initial,
     and really significant, problem is whether the product
     was duly safe or not. A good pair of shoes size 5 is
     not unduly unsafe because it may be worn by a woman
     with feet size 7 . . . . A product with adequate
     instruction for its safe use may as a result be duly
     safe, and it is not rendered unsafe by the fact that
     the consumer did not follow the instructions. . . .

     Further illustrations easily present themselves. There
     is no drug, and perhaps no food, that is not dangerous
     if too much of it is consumed. It is missing the real
     point to pose the issue in terms of whether the
     plaintiff was contributorily negligent in taking too
     many pills or too much food.


Wade, supra, at 846 (footnotes omitted).   The analysis does not

center on the due care vel non of the consumer but rather

highlights whether a product is duly safe for its intended use.

     This is true of all of the Wade factors.   For example, the

focus of the sixth factor, which considers "the user's

anticipated awareness of the dangers inherent in the product and

their avoidability, because of general public knowledge of the

obvious condition of the product, or of the existence of suitable

warnings or instruction," is on the product:

          [T]he dangers of a hoe or an axe
     are both matters of common knowledge and
     fully apparent to the user. But it is not
     necessarily sufficient to render a product
     duly safe that its dangers are obvious,
     especially if the dangerous condition
     could have been eliminated. A rotary lawn
     mower, for example, which had no housing
     to protect a user from the whirling blade
     would not be treated as duly safe, despite
     the obvious character of the danger.

     Note that the question here is whether the
     product possesses the quality of due safety,
     not whether the plaintiff assumed the risk
     or was contributorily negligent.



                               29
Id. at 842-43.

     Thus, insofar as the fifth Wade factor inquires into the

(objective) conduct of the average product user as a factor that

may justify a more or less exacting design depending on the

facts, it seems to be an appropriate ingredient in the Wade risk-

utility balance, which itself seems a useful approach to

performing the Azzarello threshold analysis.      We thus predict

that the Pennsylvania Supreme Court would follow that approach.

But only that Court can tell us, see Hakimoglu, 70 F.3d at 302-

304 (Becker, J., dissenting), and we hope that it will do so

soon.

     Properly applying the fifth Wade factor to determine the

objective user's ability to avoid danger by the exercise of care

in the use of the profiler, we find that the factor weighs

slightly in Surace's favor.       Although an individual working on

the ground behind the profiler could, in theory, avoid danger by

exercising care to always remain out of the machine's blind spot,

it seems likely that ordinary workers at a highway construction

site will occasionally find it necessary to step behind the

machine, and that such workers may, like Surace, be habituated to

the profiler's alarm and thus unable to avoid danger if the

profiler's operator backs up without signaling.

             3.   Other Wade Factors

     We do not discuss the other Wade factors except in passing

because they are either neutral or favor Surace in the risk-

utility balance.     The profiler is, of course, useful and

desirable.    (Wade factor one)    There does not appear to be a


                                    30
substitute product that would meet the same need and not be

unsafe. (factor three)     Finally, it seems feasible for the

manufacturers to spread any loss implicated by a safer design in

a variety of ways. (factor seven)

            4.   Summary

     We have rejected both the factual and legal bases of the

district court's holding that the profiler was not defective as a

matter of law, and conclude that the threshold Azzarello test has

been met.    Specifically, when we evaluate the risk-utility

factors in the light most favorable to Surace, we conclude that

the profiler may pose a grave risk of harm absent a

lockout/tagout device, in view of the phenomenon of habituation.

 The summary judgment must therefore be set aside and the case

must go to the jury, though, of course, the jury may find for the

defendant if it determines that the facts do not support a

finding of defect.     See supra at 13.

     There is, however, one other problem in the case -- that

presented by the district court's conflation of the causation

issue into the Azzarello analysis.
     III.   CAUSATION; SEPARABILITY FROM AZZARELLO ANALYSIS

     In a footnote in its opinion, the district court indicated

that, although contributory negligence is irrelevant in a strict

liability case, consideration of Surace's conduct in wearing the

earplugs and turning his back to the machine was appropriate as

part of the Azzarello threshold analysis to the extent that it

bears on causation. Surace, 1995 WL 495123 at *8 n.10.    We hold

that it was error for the district court to have weighed the



                                  31
issue of causation as a factor in resolving the legal question of

risk allocation.

     There are two elements to a strict liability claim.      The

plaintiff must establish that: (1) the product was defective; and

(2) the defect was a proximate cause of the injury. See

Berkebile, 337 A.2d at 898.    It is only the first element that a

court must address as part of the Azzarello threshold analysis.

See Azzarello, 480 Pa. at 556-58, 391 A.2d at 1025-26; see also

Hon v. Stroh Brewery Co., 835 F.2d 510, 512-13 n.3 (3d Cir. 1987)

(focusing on whether the product was defective under Azzarello

and specifically declining to address proximate cause); Phillips

v. A-Best Prods. Co., 542 Pa. 124, 131, 133 n.7, 665 A.2d 1167,

1171, 1171 n.7 (1995) (noting that its decision rested not on

whether the product was defective under Azzarello, but rather on

the lack of causation).   This threshold analysis focuses on the

condition of the product at the time it is marketed, and whether

that condition justifies placing the risk of loss on the

manufacturer.   Azzarello, 480 Pa. at 559, 391 A.2d at 1027.

     If the plaintiff ultimately proves that the product is

defective, then the distinct question of whether the defect

proximately caused the injury must be resolved. Pacheco v. Coats
Co., 26 F.3d 418, 422 (3d Cir. 1994); see generally Wade, supra,

at 842-43.   Should the court determine that the defect was not a

legal cause of the injury, then the defendant is entitled to

judgment as a matter of law.    Although the district court

followed the correct methodology in balancing the profiler's

inherent risks against its utility, it erred in factoring the


                                 32
specific circumstances surrounding the cause of the injury into

this threshold inquiry.
     IV.   ALTERNATIVE GROUNDS FOR SUMMARY JUDGMENT

     CMI moved for summary judgment on several alternative

grounds that the district court did not reach.   In view of the

foregoing discussion, we must reach them. See United States v.

Taylor, 98 F.3d 768, 774 (3d Cir. 1996) (citing Colautti v.

Franklin, 439 U.S. 379, 397 n.16, 99 S. Ct. 675, 686 n.16, 58

L.Ed.2d 596 (1979) (appellee may assert any ground in support of

the judgment below, whether or not that ground was relied upon or

even considered by the district court)), cert. denied, -- U.S.

00, 117 S. Ct. 1016, -- L.Ed.2d -- (1997).   Only two of these

grounds merit discussion.15

           A. Intended Use

     The district court observed in a footnote in its opinion

that the evidence suggested the profiler was not being used as

intended at the time of the accident.   Under Azzarello, the

inquiry is whether the product was safe for its intended use.

Azzarello, 480 Pa. at 559, 391 A.2d at 1027; Marshall, 426 Pa.

Super. at 162, 626 A.2d at 624.    Although it did not rely on this

basis in granting summary judgment, the district court opined

that "[i]t is doubtful that Plaintiffs would be able to convince

[the district court], or a jury, that using the profiler without

     15
        CMI also sought summary judgment on the grounds that the
profiler had been "substantially changed" and that Surace's
conduct was the sole cause of the accident, but these claims are
patently lacking in merit.




                                  33
the conveyor system was a way in which the profiler was intended

to be used." Surace, 1995 WL 495123, at *9 n.11.

     On appeal, CMI continues to assert that liability should not

be imposed because the profiler was not used as intended.    CMI

submits that the profiler was not meant to mill rumble strips,

and that it was not meant to be operated without the conveyor

attached.   Because the profiler was being operated without the

conveyor attached, the debris generated by it had to be picked up

manually.   At the time of the accident, Surace was sweeping or

shoveling debris out of its pathway.    Surace testified that this

was both the first time he had ever worked with the profiler

without the conveyor attached, or that anyone had been injured

when the machine was in back-up mode.

     It is clear that "[u]nless the use giving rise to a strict

liability cause of action is a reasonably obvious misuse

. . . or unless the particular use . . . is clearly warned

against, the manufacturer is not obviously exonerated." Metzgar

v. Playskool, Inc., 30 F.3d 459, 465 (3d Cir. 1994).    CMI's

Engineering Manager John Frost Phillips testified that the

machine was not intended to be operated without the conveyor

attached, and that it was not intended to mill rumble strips.

Although Phillips testimony is probative, there was no warning in

the manual indicating that the conveyor should not be removed.

Moreover, the profiler had an on/off switch to control the

conveyor and, obviously, the profiler could be operated without

the conveyor attached and used to mill rumble strips.   We hold

that, on the record before us, it cannot be determined as a


                                34
matter of law that such use of the profiler was a "reasonably

obvious misuse."    Accordingly, this cannot serve as an

appropriate basis for summary judgment.

           B.   Assumption of Risk

     CMI argues that it is entitled to summary judgment because

Surace assumed the risk of his injuries.    Assumption of the risk

is a viable defense to strict liability actions. McCown v.

International Harvester Co., 463 Pa. 13, 15, 342 A.2d 381, 382

(1975).   To prevail on an assumption of the risk defense, a

defendant must show "that the plaintiff knew of the defect and

voluntarily and unreasonably proceeded to use the product or

encounter a known danger." Wagner v. Firestone Tire & Rubber Co.,

890 F.2d 652, 657 (3d Cir. 1989)(citation omitted). "[W]hether

the plaintiff knows of the existence of the risk, or whether he

understands and appreciates its magnitude . . . is a question of

fact, usually to be determined by the jury under proper

instructions from the court.   The court may itself determine the

issue only where reasonable men could not differ as to the

conclusion." Mucowski v. Clark, 404 Pa. Super. 197, 202, 590 A.2d

348, 350 (1991) (quoting Staymates v. ITT Holub Indus., 364 Pa.
Super 37, 49, 527 A.2d 140, 146 (1987)).

     CMI asserts that Surace was aware of the danger of being in

the path of the profiler while it was operating.     To infer

assumption of the risk from Surace's conduct, the conduct “must

be such as fairly to indicate that [Surace was] willing to take

his chances." Wagner, 890 F.2d at 657 (quoting Restatement
(Second) of Torts § 496C, comment h).     It is undisputed that



                                 35
Surace was responsible for signaling the operator when to reverse

and that Snyder reversed the profiler without waiting for a

signal from Surace.   The evidence further indicates that Snyder

had never before reversed the profiler without being signaled.

Moreover, there is no evidence that Surace knew that, due to

habituation, he was unlikely to hear the profiler's backup alarm

if Snyder should advance without signaling.     Therefore, the

evidence is insufficient to establish as a matter of law that

Surace knowingly assumed the risk of injury when he stepped into

the profiler's pathway.   Accordingly, summary judgment is not

warranted on this ground.
     V.   BRINK'S EXPERT TESTIMONY

     Surace challenges the district court's exclusion of Harold

R. Brink as an expert witness.   Surace had proffered Brink, an

electromechanical engineer, to testify to the inadequacy of the

profiler's warning devices from an engineering standpoint.

Brink's "expert opinion" was that the profiler was defective

because of the obstructed view, and that the back-up alarm was

insufficient to alert crew workers because of the phenomenon of

habituation.   The district court excluded Brink's testimony,

concluding that he did not meet the Supreme Court's test for the

admission of expert witnesses set forth in Daubert v. Merrell Dow

Pharmaceuticals, 509 U.S. 579, 113 S. Ct. 2786, 125 L.Ed.2d 469

(1993), and interpreted by us in In re Paoli R.R. Yard PCB

Litig., 35 F.3d 717 (3d Cir. 1994) ("Paoli").    "A district

court's ruling on admissibility of evidence is reviewed for abuse

of discretion, `but to the extent the district court's ruling


                                 36
turns on an interpretation of a Federal Rule of Evidence [its]

review is plenary.’" Paoli, 35 F.3d at 749.

     The district court excluded Brink's testimony under

Fed. R. Evid. 702, which provides:

          If scientific, technical, or other
     specialized knowledge will assist the trier
     of fact to understand the evidence or to
     determine a fact in issue, a witness qualified
     as an expert by knowledge, skill, experience,
     training, or education, may testify thereto in

     the form of an opinion or otherwise.

The first requirement under Rule 702 is that the witness

“proffered to testify to specialized knowledge must be an

expert.”   Paoli, 35 F.3d at 741.    Although the Rule mandates a

policy of liberal admissibility, both with respect to the

substantive as well as the formal qualification of experts, id.,

we agree with the district court that Brink did not qualify.

     Brink earned a degree in electrical engineering from Lehigh

University and has had an extensive career in electrical and

mechanical engineering, including twenty years of employment with

Mack Trucks.   However, as the district court noted, Brink's

theory of liability "hinged on habituation," an area in which

Brink has no training and no experience.    Surace contends that

through his work experience, Brink "has become highly familiar

with the concept of habituation and the need to avoid this

phenomenon when designing construction machinery."     But the

record does not support this contention.    Regarding habituation,

Brink only averred generally that "over the years, I've learned

that people can tune things out."    Significantly, his testimony



                                37
focuses on making the machines "user friendly" as opposed to

considering the safety implications of a device.16

        Moreover, there is no evidence in the record that Brink had

experience in designing equipment from a human safety standpoint.

 Indeed, in his deposition testimony, Brink testified that he did

not design back-up alarms; rather they were purchased by Mack and

he would make sure they were mounted and wired properly.    Brink

further stated that he did not remember ever having tested back-

up alarms, and that his knowledge of back-up alarm systems is

limited to the extent to which they could be considered part of

the design of an electrical/mechanical system.

        Although he was a member in the Human Factors Society, Brink

admitted that he had not read any literature on the phenomenon of

habituation stemming from the alarms on construction machinery,

nor had he ever participated in a habituation testing or study.

Most significantly, Brink admitted that he relied on Dr. Lambert

as the sole authoritative basis for his conclusions regarding

habituation.     Indeed, when questioned about the specifics of

habituation, Brink replied "I'll let [Lambert] be the expert on

   16
       For example, Brink described his human factors experience
as follows:
Everything was aimed at making it as easy as possible
          for the person to operate the vehicle as far
          as locations of instruments and controls,
          location of steps for entrance and egress . .
          . we tried to design our product that was as
          manufacturable and maintainable as possible.
            So to that extent, we always had human
          factors in our mind       . . . . We never
          called it human factors, but we were
          interested in how the product related to the
          customer or user.



                                  38
this."     While we have recognized that there is no set litmus test

to qualify as an expert, see Hammond v. International Harvester

Co., 691 F.2d 646, 653 (3d Cir. 1982) (permitting person with

sales experience in automotive and agricultural equipment, who

had also taught high school automobile repair, to testify as an

expert witness in products liability action involving tractors),

there is no evidence in the record to suggest that Brink

possesses sufficient knowledge of the phenomenon of habituation,

either through training or experience, to testify as an expert.

Because habituation was the crux of his theory of liability, and

indeed the central issue of design defect in the case, the

district court properly concluded that Brink did not qualify as

an expert.
     VI.    CONCLUSION

     For the foregoing reasons, the judgment of the district

court will be reversed and the case remanded for further

proceedings consistent with this opinion.    However, the judgment

will be affirmed insofar as it precluded the Brink expert

testimony.




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