CHRISTOFFERSON v. MICHELIN TIRE CORPORATION (1990)

INTRODUCTION

In 1977, the plaintiff, Ronald Christofferson, sustained serious, permanent injuries in a single-vehicle traffic accident which occurred while he was riding a Kawasaki motorcycle equipped with Michelin tires and inner tubes.   He filed the underlying lawsuit, naming Kawasaki Heavy Industries, Kawasaki Motors Corporation (collectively, Kawasaki) and Michelin Tire Corporation (Michelin), among others, as defendants.   Kawasaki settled with plaintiff prior to trial.   Michelin appeals from the judgment entered ($1,591,880) following a jury trial which resulted in a verdict finding Michelin 83 percent liable for plaintiff's injuries.¹

The principal issue presented is whether the trial court erred in refusing to disclose to the jury a so-called “Mary Carter” sliding-scale settlement agreement ² entered into by plaintiff and Kawasaki, where disclosure was sought pursuant to Code of Civil Procedure section 877.5 to establish the possible bias of plaintiff's expert witnesses who had previously been retained by Kawasaki to study the cause of the accident.   Michelin also assigns as error the trial court's admission of certain demonstrative evidence and expert testimony based thereon and its failure to valuate and give Michelin an offset against the judgment for Kawasaki's guarantee to plaintiff of a minimum $1,000,000 judgment and plaintiff's use of Kawasaki's work product and experts.   We reverse the judgment.³

The FACTS

The Accident

A detailed recitation of the facts surrounding the accident is unnecessary.   It suffices to say that on August 3, 1977, the plaintiff, Ronald Christofferson, an on-duty California Highway Patrol (CHP) officer, lost control of his Z900 special police model Kawasaki motorcycle, equipped with Michelin M45 tires and 19 BF model Michelin inner tubes, as he was traveling eastbound on the Santa Monica Freeway.   Motorcycle and rider fell to the road and spun toward the center divider.   The plaintiff slammed into a fence pole, sustaining permanently disabling injuries to his brain stem, and radial nerve damage.   He filed suit against Kawasaki and Michelin on theories of negligence, strict liability in tort and breach of warranty, claiming, in essence, that defects in his CHP-issued motorcycle and tires caused the accident.

The “Mary Carter” Agreement

In February 1986, plaintiff settled his claim against Kawasaki.   Under the terms of the settlement agreement, plaintiff released Kawasaki from any claim;  Kawasaki immediately paid plaintiff $200,000 and guaranteed payment of additional amounts up to $800,000 depending upon the outcome of plaintiff's claim against Michelin.   The “Mary Carter”-style agreement provided for different payment schedules depending upon whether plaintiff settled with Michelin, or the claim against Michelin was decided by a jury.   At the two extremes, if Michelin agreed to settle the case and pay plaintiff an amount equal to or higher than $1,120,000, Kawasaki was obligated to pay nothing and plaintiff was obligated to return to Kawasaki its $200,000 payment;  if a jury trial resulted in a defense verdict for Michelin, Kawasaki was obligated to pay plaintiff an additional $800,000.

Kawasaki moved for confirmation of the settlement as one in “good faith.”  (Code Civ.Proc., § 877.6.) ⁴  Neither Kawasaki's moving papers nor the settlement agreement itself contained any reference to the possible use of Kawasaki's expert witnesses or work product by plaintiff.   Kawasaki's moving papers contained a statement asserting that “by removing Kawasaki as a defendant in the main action, this settlement frees Michelin from the fear that Kawasaki may join with the plaintiff in attacking Michelin's products.” ⁵

The proposed “Mary Carter” agreement was unopposed by Michelin and the trial court found the settlement to be in good faith at a hearing held on February 10, 1986.

The Battle of Experts and the Kovach Experiments

Because plaintiff had amnesia about the events surrounding the accident and eyewitness accounts were, at best, inconclusive, the trial was dominated by expert witnesses espousing different theories of how and why the accident occurred.

Plaintiff's theory of the case was that defects in the Michelin tube in the motorcycle's front tire were responsible for setting in motion a series of events culminating in the accident.   To wit:  defective manufacture of the tube resulted in pin holes in the rubber and cracking around the valve stem which in turn allowed air to leak from the tube.   The partially deflated tube then experienced movement within the tire.   The movement of the tube applied stress to the tube's valve stem which is usually, but was not in this case, secured with a lock washer.   The valve stem could not withstand the stress because of improper adhesion between the valve stem and the body of the tube.   Consequently, the valve stem was ripped from the tube and the front tube suddenly lost all remaining pressure.   While struggling to retain control of his motorcycle, plaintiff hit the berm at the edge of the highway which caused him to completely lose control of the motorcycle and hit the center divider.

Michelin's theory of the case was that the pin holes in the tube had been caused by rust on the inner surface of the wheel rim, which in turn had been caused by defective plating of the wheel by Kawasaki.   According to Michelin's experts, the accident was initiated when a severed or abraded brake line sprayed brake fluid on plaintiff's leg and lower body.   The spray distracted plaintiff and caused him to stray on to the berm at the edge of the highway.   Plaintiff thereupon lost control of his motorcycle and was injured.

Plaintiff called five expert witnesses to prove his theory of the case and discredit Michelin's contention that rust from the wheel rim caused pin holes in the tube of the tire.   Two of the experts, James Johnson and Herbert Hinden, had no prior affiliation with Kawasaki.   Johnson, a former Michelin field engineer, was a staff engineer for Vollmer–Gray Engineering, specializing in tire failure evaluation.   Hinden, also a former employee of Michelin, was an independent consultant in the field of tire, tube and wheel failure.

Three other expert witnesses, Stephen Cannon, Robert Kovach, and William Otto, were private consultants originally retained as experts by Kawasaki.   Otto was an independent consultant specializing in accident reconstruction.   He was contacted by Kawasaki's counsel in 1982 and asked to inspect plaintiff's motorcycle to determine how the accident occurred.   As of 1983, Otto had been involved for Kawasaki in 80 to 120 cases.   At the time of trial, Otto's consulting firm was actively involved in several accident cases on Kawasaki's behalf.

Cannon, a specialist in the area of adhesive coatings, fibers, films, and elastomerics (scientific polymeric rubber materials), was invited to become involved in the evaluation of plaintiff's accident by William Otto.   This occurred sometime between 1980 and 1982.   Cannon was aware that Otto was investigating the matter on behalf of Kawasaki and had worked with Otto on one other Kawasaki matter.   At the time of trial, he had thrown away his files on the case and could no longer recall who, if anyone, he billed for his time.

Kovach, a forensic reconstructionist with a specialty in motorcycles, was first contacted by Kawasaki's counsel in 1983 or 1984 and asked if he could supply some in-police-service motorcycle rims, tubes and tires.   He had minimal involvement in the case at that time.   In the spring of 1987, after Kawasaki had settled with plaintiff, Kovach was again contacted by Kawasaki's counsel and retained by Kawasaki to investigate the cause of plaintiff's accident.   With the assistance of two Kawasaki technicians, Bill Zito and Fred Tunstall, Kovach conducted certain tests using exemplary 1975 and 1976 Kawasaki Z900 police special motorcycles like the one ridden by plaintiff.   The purpose of the tests was not to recreate plaintiff's accident, but rather, to see if, when underinflated, Michelin front motorcycle tires were particularly susceptible to the shearing of the valve stem under conditions of precession or recession.⁶

The 1976 model motorcycle was equipped with Dunlop tires with Yokohama tubes and the 1975 model was equipped with Michelin M45 tires with Spanish-made Michelin 19 BF tubes.   The Michelin tube had been equipped by its previous owner with an internal compression washer and lock nut, not ordinarily supplied by Michelin.   Plaintiff's motorcycle was not so equipped at the time of the accident.

On June 10, 1987, Kovach and one of the Kawasaki technicians ran the motorcycles at a test site in the Mojave desert, gradually reducing the pressure in the tires.   At 15 psi, Kovach noticed a slight precession (less than one-quarter inch) on both tires.   Next, they reduced the pressure in the tires to approximately 8 psi.   Both motorcycles experienced very obvious tire and tube precession;  however, there was no shearing of the valve stem.   The same tests were repeated the next day with nearly identical results.⁷

On June 21, 1987, Kovach switched the brand of tire on each motorcycle in preparation for further testing.   The 1975 model motorcycle was equipped with the Dunlop tires and the 1976 model was equipped with Michelin M45 tires with an Italian-manufactured Michelin 19 BF tube.   The tube was installed as supplied by Michelin, with no internal lock nut assembly.   Kovach was surprised to see significant differences between the Spanish-made Michelin tubes and the Italian-made tubes.   When he saw the Italian-made Michelin tubes, he “knew [they] were going to pull valve stems.”

During a “stabilization ride” ⁸ on June 22, 1987, there was significant valve stem bending on the Michelin tire during routine freeway operations.   On June 24, 1987, more tests were run using the Kawasaki motorcycle equipped with an Italian-made Michelin tube.   At 15 psi, Kovach obtained minor precession after running the motorcycle for only one mile.   At 8 psi, Kovach ran the motorcycle only one mile before his front valve stem ripped out, causing a blowout.   The Yokohama tube did not rip out under identical driving conditions.

On November 6, 1987, Kovach, with the assistance of the Kawasaki technicians, ran further tests using the 1975 model Kawasaki motorcycle equipped with an Italian-made Michelin tube.   Again, at 8 psi, the valve stem on the Italian-made tube tore out.

Next, Kovach equipped the 1975 model Kawasaki motorcycle with a Spanish-made Michelin tube, as supplied by Michelin without a lock nut and washer.   At 8 psi, the Spanish-made tube also experienced valve stem shear-off, although it took longer to do so than the Italian-made tube.⁹

Kovach was not originally scheduled to be called as a plaintiff's witness.   When plaintiff's first expert, James Johnson, was called as a witness, he testified that he had considered videotapes of the Kovach experiments in forming his opinion that Michelin tires were susceptible to tearing out.   Michelin objected to Johnson's reliance upon the tests of an expert who had not been designated as a witness and was not scheduled to testify.   Plaintiff argued that Evidence Code section 801 ¹⁰ authorized Johnson to rely upon the experiments conducted by other experts, but the trial judge disagreed.   The court allowed Johnson to testify regarding the Kovach experiments, subject to a motion to strike if Kovach were not called as a witness to describe his own experiments, and subjected to cross-examination.¹¹  A brief recess was taken to permit Michelin to depose Kovach.   Thereafter he was called as a plaintiff's witness over Michelin's strenuous objection that testimony about the experiments should be excluded because the tests were not conducted under conditions sufficiently similar to those of plaintiff's accident.

Motion for Disclosure of the “Mary Carter” Agreement

Before plaintiff called Mr. Kovach as an expert witness, Michelin moved for disclosure of the sliding scale agreement between plaintiff and Kawasaki under Code of Civil Procedure section 877.5, subdivision (a)(2).   That section provides:  “(a) Where an agreement or covenant is made which provides for a sliding scale recovery agreement between one or more, but not all, alleged defendant tortfeasors and the plaintiff or plaintiffs:  ․ [¶]  (2) If the action is tried before a jury, and a defendant party to the agreement is called as a witness at trial, the court shall, upon motion of a party, disclose to the jury the existence and content of the agreement or covenant, unless the court finds that such disclosure will create substantial danger of undue prejudice, of confusing the issues, or of misleading the jury.”   Michelin argued that because Kawasaki had a financial interest in the outcome of the trial and Kovach had initially been hired as its expert, disclosure of the sliding scale settlement agreement was proper to establish the witness's possible bias.¹²  Plaintiff asserted that disclosure was not authorized by section 877.5 because Kovach was not a Kawasaki employee, was not a party to the settlement agreement, and was paid by plaintiff, not Kawasaki, for his expert testimony at trial.   The trial court denied the motion without explanation.¹³

The Motion for Valuation and Offset

Prior to trial, Michelin moved for a pretrial valuation of Kawasaki's guarantee to plaintiff of an additional $800,000 recovery, seeking credit against any future judgment for the $200,000 paid to plaintiff plus the value of the guarantee itself.   The trial court indicated that it would read the legal authority relied upon by Michelin (Abbott Ford, Inc. v. Superior Court, supra, 43 Cal.3d 858, 239 Cal.Rptr. 626, 741 P.2d 124), and “think about that.”

The issue of valuation of the guarantee was next taken up at Michelin's motion for new trial.   Michelin requested valuation of and credit against the judgment for the guarantee, and in addition, for Kawasaki's release of its experts and work product to plaintiff.   The court granted Michelin a $200,000 setoff for the amount actually paid by Kawasaki to plaintiff pursuant to the settlement, but no credit against the judgment for the value of the guarantee itself and use of Kawasaki's experts.¹⁴

DISCUSSION

IThe Admissibility of Evidence of the Settlement Agreement

 Whenever a sliding scale recovery agreement is made between one or more, but not all, alleged defendant tortfeasors and the plaintiff or plaintiffs, disclosure of the agreement to the jury is mandatory under section 877.5, subdivision (a)(2), if “a defendant party to the agreement is called as a witness at trial ․ unless the court finds that such disclosure will create substantial danger of undue prejudice, of confusing the issues, or of misleading the jury.”   In this case, Kawasaki was the only defendant party to the settlement agreement.   We are asked to decide whether Kawasaki was, in effect, “called as a witness at trial” within the meaning of section 877.5 when plaintiff presented the testimony of experts formerly employed by Kawasaki to affix blame for the plaintiff's motorcycle accident.

 Whether or not section 877.5 mandates disclosure under the circumstances of this case depends upon how the phrase “defendant party to the agreement” is construed when the settling party is a corporation.   Did the Legislature intend to require disclosure if and only if a corporate defendant party to a sliding scale settlement agreement is called as a witness through its duly appointed officers and/or employees, or did it also intend to compel disclosure when such a corporate party offers evidence against nonsettling defendants through third nonparty witnesses who nonetheless advance the corporation's interests?  “In construing a statute ‘we begin with the fundamental rule that a court “should ascertain the intent of the Legislature so as to effectuate the purpose of the law.” ’ ”  (California Teachers Assn. v. San Diego Community College Dist. (1981) 28 Cal.3d 692, 698, 170 Cal.Rptr. 817, 621 P.2d 856;  cit. omitted.)

Prior to the enactment of section 877.5, so-called “Mary Carter” settlement agreements were permissible.   Yet generally such agreements were not required to be revealed to the jury in a subsequent trial between the plaintiff and nonsettling defendants.  (Legis. Counsel's Dig., Assem. Bill No. 1275, Stats. 1977 (Reg. Sess.) Summary Dig., p. 138.)  “Mary Carter”-type agreements were thus vulnerable to abuse.   One or more defendants in a multi-defendant tort action could enter into such an agreement and effectively defeat the equitable sharing of costs among parties at fault (see Abbott Ford, Inc. v. Superior Court, supra, 43 Cal.3d at p. 872, 239 Cal.Rptr. 626, 741 P.2d 124) by colluding with the plaintiff to secure a disproportionate judgment against the remaining, nonsettling defendants.  (See Sen. Com. on Judiciary, Analysis of Assem. Bill No. 1275 as amended Aug. 3, 1977 (1977–1978 Reg. Sess.).)   Section 877.5 was adopted to counter “the collusive nature of such agreements and the unfair prejudice to the non-settling defendant” (Moreno v. Sayre (1984) 162 Cal.App.3d 116, 125, 208 Cal.Rptr. 444), and to “prevent the abuse of current tort contribution provisions by plaintiffs.”  (Sen. Com. on Judiciary, Analysis of Assem. Bill No. 1275, supra, at p. 1.)

As originally enacted, section 877.5 limited disclosure to “no more than necessary to be sure that the jury understands (1) the essential nature of the agreement, but not including the amount paid, or any contingency, and (2) the possibility that the agreement may bias the testimony of the alleged tortfeasor or tortfeasors who entered into the agreement.”  (See Stats.1977, ch. 568, § 1, p. 1798.)   In 1987, the statute was amended to permit, without limitation, disclosure of “no more than necessary to inform the jury of the possibility that the agreement may bias the testimony of the witness.”  (See Legis. Counsel's Dig., Assem. Bill 344, Stats.1987 (Reg.Sess.) ch. 1202, p. 1.)

Plaintiff would have us find the provisions of section 877.5 inapplicable to compel disclosure so long as a defendant party to a “Mary Carter”-type agreement is clever enough to present its case against the remaining, nonsettling defendants through the testimony of individuals lacking the status of officers and employees.   We think that such a construction defeats the underlying statutory intent to neutralize the collusive effect of “Mary Carter” agreements and prevent abuses of the tort contribution system.   The intent underlying section 877.5 is best effectuated by an interpretation of that provision which recognizes that corporate parties to “Mary Carter” agreements may, in a subsequent trial, “testify” for the plaintiff through persons not customarily considered agents in other legal contexts.  (See 2 Witkin, Summary of Cal. Law (9th ed. 1987) § 13, pp. 29–30.)

It appears that the trial court excluded the evidence of the “Mary Carter” agreement based upon a contrary reading of the statute.   This was error.   Under section 877.5, disclosure of the agreement was mandatory if Kawasaki was, in effect, called as a witness through a third nonparty whose testimony nonetheless advanced Kawasaki's interest in a large plaintiff's verdict.

Plaintiff asserts, in essence, that Kawasaki was not “called as a witness” because there was never an agency relationship between the corporation and the expert witnesses.   Manifestly, a corporate entity cannot testify except “ ‘through the agency of natural persons.’ ”  (Monteleone v. Southern California Vending Corp. (1968) 264 Cal.App.2d 798, 806, 70 Cal.Rptr. 703;  (cit. omitted.)   The requisite agency relationships were assertedly lacking because the witnesses, including Kovach, were all independent contractors with no financial interest in the outcome of the trial.   However, “[a]gency and independent contractorship are not necessarily mutually exclusive legal categories as independent contractor and servant or employee are.   In other words, an agent may also be an independent contractor.”  (City of Los Angeles v. Meyers Bros. Parking System, Inc. (1975) 54 Cal.App.3d 135, 138, 126 Cal.Rptr. 545;  see also Doctors' Co. v. Superior Court (1989) 49 Cal.3d 39, 46, fn. 4, 260 Cal.Rptr. 183, 775 P.2d 508.)

It is undisputed that Kovach was hired by Kawasaki, through its attorney, to conduct tests to determine the susceptability of Michelin tires to valve shearing.   Kawasaki technicians not only assisted Kovach, they co-participated in the experiments by acting as motorcycle operators during test drives.   Kawasaki's lawyer was an observer during at least one of the test sessions.   Kawasaki did not just “release” its test data to plaintiff upon settlement, as respondent suggests.   From the outset, the commissioning of valve shearing experiments by Kawasaki, a decade following the plaintiff's accident and more than a year following settlement, would appear to have been for the purpose of garnering evidence for plaintiff's use at trial.

 Ordinarily, the existence of an agency relationship is a preliminary fact for determination of the trial court.  (Evid.Code, § 400;  Brokaw v. Black–Foxe Military Institute (1951) 37 Cal.2d 274, 278, 231 P.2d 816.)   Here, however, the circumstances admit of only one reasonable inference.   In conducting the valve shearing tests upon Michelin tires, Kovach was more than just an independent contractor;  he was plainly acting as Kawasaki's agent as well.  (See, e.g., City of Los Angeles v. Meyers Bros. Parking System, Inc., supra, 54 Cal.App.3d at p. 138, 126 Cal.Rptr. 545;  Casselman v. Hartford A. and I. Co. (1940) 36 Cal.App.2d 700, 709–711, 98 P.2d 539.)

It is true that neither Kovach nor plaintiff's other expert witnesses had a direct financial interest in the outcome of the trial.   However, for those who earn a living as private consultants and expert witnesses, a jury verdict in favor of a litigant for whom one has testified is hardly without its indirect pecuniary rewards.   Certainly Kovach, and the other plaintiff's experts who relied upon his test data, might reasonably have expected to reap some business advantage from a verdict relieving Kawasaki of a sizeable financial obligation to the plaintiff.

Respondent argues that, at the time of trial, Kovach was no longer an agent for Kawasaki because any relationship ended when Kovach's work for Kawasaki was finished, and Kovach was thereafter solely in plaintiff's employ.   We think it fatuous to assume that any bias or interest on the part of Kovach suddenly evaporated upon completion of the investigation for Kawasaki.   The witness' testimony, while paid for by plaintiff, related to elaborate experimental procedures conducted for the mutual benefit of plaintiff and Kawasaki at Kawasaki's direction and expense.   Kovach's relationship with Kawasaki at the time of the valve shearing tests was surely relevant to the jury's assessment of the credibility and validity of Kovach's test data and professional opinion.  (Cf. Gray v. Davis Timber and Veneer Corp. (Ind.App.1982) 434 N.E.2d 146, 148.)

Respondent alternatively contends that it was sufficient for impeachment purposes that the jury was apprised of the past employment relationships between Kawasaki and the plaintiff's key expert witnesses.   Evidence of a prior employment relationship was, however, of limited value to the jury in weighing the credibility of the experts because essential information regarding Kawasaki's past and present financial interest in the outcome of the lawsuit was withheld.  (Cf. Thurber Corporation v. Fairchild Motor Corporation (5th Cir.1959) 269 F.2d 841, 845.)

 In enacting section 877.5, the Legislature stated in unmistakable terms its intent to prevent unfair collusion between plaintiffs and settling defendants to defeat the equitable sharing of costs among parties at fault.   That purpose was defeated by nondisclosure of the settlement agreement to the jury, merely because Kawasaki chose to present its case against Michelin through the agency of natural persons other than officers or employees of the corporation.   The trial was without question, a battle of the experts.   The valve shearing experiments conducted by Kovach and relied upon by a majority of plaintiff's experts constituted undeniably potent evidence that a defect in Michelin's tires was the cause of plaintiff's accident.   Yet the jury was not informed of the possibility that the settlement agreement infected the test protocol or influenced the testimony of experts formerly employed by Kawasaki.   This permitted plaintiff to falsely portray his expert witnesses as having no conceivable economic or other interest in the outcome of the trial to Michelin's substantial prejudice.

The case appears to have been closely balanced.   Jury deliberations consumed eight days and resulted in a divided verdict, nine to three in favor of the plaintiff.   Had the jury been aware that Kawasaki stood to benefit greatly from a favorable plaintiff's verdict, it might well have viewed the valve shearing studies, and expert testimony based thereon, in a somewhat different manner.  (See General Motors Corp. v. Lahocki (1980) 286 Md. 714, 410 A.2d 1039, 1045.)   Reversal is accordingly required.  (Cf. Barajas v. USA Petroleum Corp. (1986) 184 Cal.App.3d 974, 989, 229 Cal.Rptr. 513;  Moreno v. Sayre, supra, 162 Cal.App.3d at p. 127, 208 Cal.Rptr. 444.)

II

Admissibility of the Kovach Accident Simulations

The admissibility of the Kovach accident simulation data has also been challenged on appeal.   The issue must be addressed because of the likelihood that it will again arise on retrial.

 “Experimental evidence is, of course, admissible where it (1) is relevant, (2) was obtained under conditions substantially similar to those to which it is sought to be applied, and (3) will not cause undue delay in the trial or confusion for the jury.”  (Hasson v. Ford Motor Co. (1977) 19 Cal.3d 530, 548–549, 138 Cal.Rptr. 705, 564 P.2d 857;  see also Culpepper v. Volkswagen of America, Inc. (1973) 33 Cal.App.3d 510, 521, 109 Cal.Rptr. 110.)   Michelin asserts that there were deficiencies in all three foundational prerequisites for admission.   The main thrust of the argument is that plaintiff's experts generally testified that the tire valve was sheared through recession whereas, in the Kovach tests, valve shearing was precipitated through precession—“a totally different process.”

The argument depends upon a characterization of the evidence which is neither complete nor accurate.   In fact, one of plaintiff's experts (William Otto) testified that the valve stem had probably already been separated from the stem patch and tube by precession at the time the final tearing out of the stem occurred during braking, under conditions of recession.   Another (James Johnson) was asked to reexamine plaintiff's front motorcycle tire during cross-examination and thereafter opined—based upon marks observed under the improved lighting conditions of the courtroom—that the valve appeared to have torn out under conditions of precession rather than recession.   Hence, there was evidence to suggest that both precession and recession contributed to the weakening and failure of the plaintiff's Michelin tire.

 Michelin contrasts, in several other respects, the conditions under which the valve shearing experiments were conducted and the conditions under which plaintiff's tire actually failed.   Michelin points out, for example, that there were differences in tire pressure and lubrication, air temperature and road surface.   However, “[t]he standard that must be met in determining whether the proponent of the experiment has met the burden of proof establishing the preliminary fact essential to the admissibility of the experimental evidence is whether the conditions were substantially identical, not absolutely identical.”  (Culpepper v. Volkswagen of America, Inc., supra, 33 Cal.App.3d at p. 521, 109 Cal.Rptr. 110;  see also People v. Roehler (1985) 167 Cal.App.3d 353, 386, 213 Cal.Rptr. 353.)

 In exercising its discretion whether to admit experimental evidence, a trial court is required to weigh the probative value of the evidence against the danger of prejudice, confusion of the jury and undue time consumption.  (People v. Roehler, supra, at p. 386, 213 Cal.Rptr. 353.)   Such evidence is relevant if it has “any tendency in reason to prove or disprove any disputed fact that is of consequence to the determination of the action.  (Evid.Code, § 210.)”  (Ibid.)  The Kovach experiments are highly relevant to prove that the Michelin tires with which plaintiff's motorcycle was equipped were particularly susceptible to valve shearing under conditions of precession and recession, and that such susceptibility could have been prevented by the use of a lock nut and washer.   The dissimilarities referred to by Michelin do not, as a matter of law, require exclusion of the Kovach experiments.   The jury may, of course, consider any differences in circumstance in determining the weight to be accorded this evidence.

Valuation of the Settlement Agreement

 The settlement between Kawasaki and plaintiff was reached before Abbott Ford, Inc. v. Superior Court, supra, 43 Cal.3d 858, 239 Cal.Rptr. 626, 741 P.2d 124 clearly articulated the necessity for parties to assign monetary values to their sliding scale settlement agreements to facilitate the trial court's “good faith” determination under Tech–Bilt, Inc. v. Woodward–Clyde & Associates (1985) 38 Cal.3d 488, 213 Cal.Rptr. 256, 698 P.2d 159.   The parties to the “Mary Carter” settlement therefore failed to place a specific monetary value on that agreement.

Plaintiff suggests that the value of the settlement was in fact deemed by the parties to be the $200,000 which Kawasaki advanced to the plaintiff.   Whether or not a value of $200,000 meets the standards of reasonableness required by Tech–Bilt, there is simply no evidence that the parties assigned the settlement such a value.

Plaintiff alternatively asserts that Michelin waived the right to raise the valuation issue by failing to raise it at the “good faith” settlement hearing (section 877.6).   Apart from the fact that the “good faith” settlement hearing took place in February 1986, before the Supreme Court's decision in the Abbott Ford case, the notice of settlement failed to apprise Michelin of Kawasaki's intention to remain actively involved in developing expert evidence for use in plaintiff's trial against Michelin.   Indeed, the settlement documents falsely assured Michelin that Kawasaki would not thereafter join with the plaintiff in attacking Michelin's products.   Had Michelin been notified of all of the benefits derived by plaintiff under the agreement, it may well have opposed confirmation of the settlement.

Plaintiff obviously derived tremendous value from his settlement with Kawasaki.   He received a guaranty of a minimum $1,000,000 judgment.   In addition, Kawasaki absorbed plaintiff's costs of hiring an expert to develop possible demonstrative evidence for use against Michelin at trial.   On remand, if the matter is retried and results in a verdict for plaintiff against Michelin, it will be necessary for the trial court to determine the reasonable value of the settlement and offset that amount against any judgment.

The judgment is reversed.   Appellant to recover costs on appeal.

FOOTNOTES

1.   In special findings, plaintiff was found to be 4 percent liable for his injuries.   Other third nonparties were found liable for the remaining 13 percent.   Kawasaki was determined to be 0 percent liable.   The total damages were found to be $1,878,000, including $678,000 in economic damages.

2.   The term “Mary Carter” agreement was coined from one of the earliest cases involving such an agreement, Booth v. Mary Carter Paint Company (Fla.App.1967) 202 So.2d 8, and is “ ‘used rather generally to apply to any agreement between the plaintiff and some (but less than all) defendants whereby the parties place limitations on the financial responsibility of the agreeing defendants, the amount of which is variable and usually in some inverse ratio to the amount of recovery which the plaintiff is able to make against the nonagreeing defendant or defendants.’ ”  (Abbott Ford, Inc. v. Superior Court (1987) 43 Cal.3d 858, 869, fn. 9, 239 Cal.Rptr. 626, 741 P.2d 124, citing Maule Industries, Inc. v. Rountree (Fla.App.1972) 264 So.2d 445, 446, fn. 1.)

3.   Because we reverse the judgment, we need not address the additional contention that the trial court lacked jurisdiction to amend the judgment during the pendency of this appeal to correct its retroactive application of the Fair Responsibility Act of 1986 (Civ.Code, §§ 1431–1431.5)—popularly known as Proposition 51—in accordance with the Supreme Court's decision in Evangelatos v. Superior Court (1988) 44 Cal.3d 1188, 246 Cal.Rptr. 629, 753 P.2d 585.

4.   All further statutory references are to the Code of Civil Procedure unless otherwise indicated.

5.   The settlement agreement contained the following paragraph regarding plaintiff's continued representation by the law firm, Greene, O'Reilly, Broillet, Paul, Simon, McMillan, Wheeler & Rosenberg:  “From the effective date of this agreement to the conclusion of this litigation, plaintiff and his present law firm, and Gary Paul, Esq. will continue to prosecute this action against the remaining defendant, MICHELIN, in the same way that plaintiff and his attorneys would have proceeded in the absence of this agreement.   Lead trial counsel shall be Gary Paul, or Browne Greene, or Charles O'Reilly, or Bruce Broillet, or other counsel acceptable to KAWASAKI.”   Under another provision of the agreement, Kawasaki reserved the right, in the event a jury awarded plaintiff a judgment against Michelin in an amount less than $700,000, to pursue plaintiff's post-trial and appellate remedies on his behalf if he chose not to do so.

6.   As explained by respondent, “Precession ․ occurs when the tire bead does not fit tightly against the rim and the tire becomes underinflated.   When the motorcycle accelerates, the road tends to hold the tire in place.   As the wheel tries to move the tire, and as the ground tries to hold the tire in place, the tire tends to ‘walk around’ the wheel clockwise․  As the tire moves, it drags the inner tube along with it․  [¶] Recession is a similar phenomenon that occurs when a motorcyclist brakes.   In [recession], the braking wheel slows.   However, the motorcycle's continued momentum tends to impel the motorcycle tire forward along the road surface.   Again, the tire head rotates (now, counterclockwise) along the wheel rim, dragging the inner tube with it, putting stress on the valve stem assembly.”   Plaintiff's experts were generally of the opinion that in plaintiff's case, the tearing of the valve stem and accompanying loss of inflation probably occurred during braking, as the tube rotated around the rim due to recession.   This happened after the valve stem/inner tube adhesive bond had been weakened by precession.

7.   Kawasaki's attorney was present as an observer during the June 11, 1987 tests.

8.   By “stabilization ride,” Kovach was referring to pre-experiment familiarization and handling tests conducted with both motorcycles configured properly with tire air pressure set within reasonable standards.

9.   A portion of the June 24, 1987 tests, and the November 6, 1987 tests were videotaped and the videotapes were viewed by the jury.

10.   Evidence Code section 801 provides, in relevant part:  “If a witness is testifying as an expert, his testimony in the form of an opinion is limited to such an opinion as is:  ․ [¶] (b) Based on matter (including his special knowledge, skill, experience, training, and education) perceived by or personally known to the witness or made known to him at or before the hearing, whether or not admissible, that is of a type that reasonably may be relied upon by an expert in forming an opinion upon the subject to which his testimony relates, unless an expert is precluded by law from using such matter as a basis for his opinion.”

11.   An expert may not relate an out-of-court opinion by another expert as independent proof of any fact.  (Mosesian v. Pennwalt Corp. (1987) 191 Cal.App.3d 851, 860, 236 Cal.Rptr. 778.)   An expert opinion must be based upon facts personally observed or upon hypotheses supported by the evidence.  (Ibid.)  We doubt that any violation of Evidence Code section 801 would have resulted had Mr. Johnson been permitted to rely upon his personal observation of videotapes of the valve shearing experiments conducted by Mr. Kovach.   Michelin would then have been free to call Kovach as its own witness for purposes of attempting to discredit Kovach's methodology.   Nevertheless, it was within the trial court's discretion to regulate the order of proof (Evid.Code, § 320) to admit expert testimony relating to the valve shearing experiments subject to a requirement that Kovach be called as a witness and subjected to cross-examination.

12.   Similar requests for disclosure of the “Mary Carter” agreement were not made in connection with the testimony of plaintiff's other experts.   On appeal, plaintiff contends that the “Mary Carter” issue was waived with respect to two of plaintiff's experts (Cannon and Otto).   However, Mr. Otto, as well as Mr. Johnson, relied upon the Kovach experiments in formulating their expert opinions about the cause of the accident.   Under the circumstances, Michelin's single motion for disclosure of the “Mary Carter” agreement at the time of Kovach's testimony was adequate to preserve for review whether the verdict against Michelin was tainted by the jury's ignorance of Kawasaki's financial interest in the outcome of the trial.

13.   At one point during the hearing of Michelin's motion, the trial court queried, “Yes, but you can't bring in a Mary Carter, can you?”   After hearing further argument by both parties, the court denied Michelin's request for disclosure without explanation.   From the tenor of the discussion, it appears that the court was persuaded by plaintiff that evidence of the settlement was inadmissible under section 877.5 because the settling “party”—i.e., Kawasaki—did not testify as a witness at the trial.

14.   Michelin also received setoffs against the judgment for an additional $11,000 received by plaintiff from several other parties who had settled before trial.

FUKUTO, Associate Justice.

COMPTON, Acting P.J., and GATES, J., concur.