APPEAL from the Circuit Court of Cook County; the Hon. THOMAS
H. FITZGERALD, Judge, presiding.
MR. JUSTICE DEMPSEY DELIVERED THE OPINION OF THE COURT:
On February 9, 1969, Lorraine Mullen and her husband Robert were injured when Mrs. Mullen lost control of their 1967 Chevrolet station wagon and it left the highway and overturned. The immediate cause of the accident was a blowout of the left rear tire. The Mullens brought this action against the General Motors Corporation and Uniroyal, Inc., manufacturers of the vehicle and tire, upon dual theories of strict liability in tort and breach of the implied warranty of fitness. Robert Mullen died prior to the trial, from causes unrelated to the accident. A jury returned verdicts in favor of Lorraine Mullen individually, for $43,700, and as administratrix of her husband's estate, for $8,250. The defendants have appealed from the denial of their motions for a directed verdict, for judgment notwithstanding the verdict and for a new trial.
The defendants contend that the plaintiff's evidence did not establish either the existence of an unreasonably dangerous manufacturing defect or that such a condition was the proximate cause of the tire's failure. Alternatively, they contend that even if her evidence was sufficient to require the presentation of a defense, it was convincingly rebutted by the defendants' own evidence.
• 1 A preliminary observation is appropriate. In her brief the plaintiff fully recounted the facts, prefaced by the statement that this was required because the "defendants' statement of facts was not limited to only that evidence which supports the verdict and is consistent therewith." That comment reflects a misunderstanding of the standard of review. Under the prevailing rule in Illinois, a defendant is entitled to a directed verdict or a judgment notwithstanding the verdict when all the evidence, viewed in its aspects most favorable to the plaintiff, so overwhelmingly favors the defendant that no contrary verdict based on that evidence could ever stand. While the court must allow all inferences favoring the plaintiff, it must also consider and weigh the evidence which favors the defendants.
Four witnesses gave testimony for the plaintiff relating to the liability issue. Mrs. Mullen described the tire's history. The Mullens purchased the station wagon in October 1966. The left rear tire was one of five which accompanied the car as original equipment. From the time of purchase until the time of the accident, the auto was driven 23,600 miles. The Mullens used it mainly for traveling to and from a suburban railroad station, for shopping, and for pleasure. They had driven it on two extended vacation trips, to Mexico in February 1967 and to Minnesota in September 1968. When the tire blew out they were traveling at a speed of 65 to 70 miles an hour on a highway near Leasburg Spur, Missouri, en route from Chicago to Joplin, Missouri.
The station wagon had not previously been involved in an accident, nor, to Mrs. Mullen's knowledge, had it ever been driven over rough terrain or over curbs, logs, or unusual bumps. It had not been used to haul another vehicle or trailer. Only once had the Mullens experienced trouble with any of the tires on their car. As they were returning from Mexico in 1968, the right rear tire developed a slow leak and was replaced with the spare.
Mrs. Mullen was an experienced driver and aware that tires wear out, but she had paid little attention to the maintenance of the tires. She said that she and her husband had not bought tires in more than a decade, since it was their practice to trade in their car for a new model before it became necessary to replace original equipment. She had at least glanced through the owner's manual and was aware that it recommended the maintenance of certain levels of air pressure and periodic rotation of the tires, but she did not know whether the tires had ever been rotated. At intervals, she would ask gas station attendants to check the tires, but she specified no particular air pressure for them. The tires had never appeared low to her, except the one which had been replaced. Beyond knowing that there was tread on the tires she did not know their condition. The day before the Mullens departed for Joplin, they left the car at a service station, asking that the oil be changed and the car checked for a trip. Mrs. Mullen did not know the nature of the checkup. She could not say whether the car had been given a safety inspection within the 6 months preceding the accident.
After the accident, the auto was transported 5 miles to a service station. No witness described the manner in which the vehicle was moved this distance. An employee of the service station testified that the front tires were in good condition; but the left rear tire was deflated and missing a piece of its tread, and the right rear tire, although still inflated, had a bulge on the exterior sidewall. In his opinion, the left rear tire had not been run upon while flat. Thinking that the vehicle would be moved again, and believing that, due to the damage to the vehicle's front end, it could only be towed with the front end raised, he marked all the tires to indicate their original positions and then switched the rear tires and wheels to the front and the front tires and wheels to the rear.
Stanley Myers, a professional investigator, picked up the rear tires at the service station, had them photographed, and sent them to be examined by John Reffner, an expert engaged by the plaintiff. Myers noticed a decal on the car door, indicating that the last safety check on the vehicle had been conducted when the odometer showed a mileage of 20,652 miles.
Reffner was the assistant director of the Institute of Material Science at the University of Connecticut. He possessed bachelor and master of science degrees and was working toward a doctorate. His graduate study had been in the areas of rubber and polymer science, chemical microscopy and solid state chemistry. He had worked for a time in the laboratories of the B.F. Goodrich Tire and Rubber Company, testing and performing microscopic examinations of various rubber products, including tires. After joining the University of Connecticut he continued to do tire analysis part time, working for attorneys in civil actions and as consultant to two tire companies.
In April 1969 Reffner received the two rear tires of the Mullen automobile from Myers. They still bore the identifying chalk marks placed on them by the service station attendant in Missouri. Reffner thought that the right rear tire appeared normal and he did not examine it further. The left rear tire he examined visually. He found scuffing and abrasion on the sidewall areas which he testified most probably occurred as a result of the accident. The most significant damage was an opening in the shoulder of the tire carcass, where the interior sidewall met the tread. Above this opening, a piece of sidewall and tread rubber was missing from an area which measured three inches by five inches, along the edge of the sidewall and reached around to the second tread groove. Reffner viewed this area through a stereobinocular microscope and photographed it close up and in low magnification.
Before explaining his opinion why the tire had failed, Reffner discussed the construction of tires generally. He said that the tread is merely the wearing surface that comes in contact with the road and does not significantly contribute to a tire's total strength. That depends upon a tire's internal structure, which in this case consisted of fabric plies, each made up of parallel cords. To increase strength, the plies are laid on one another so that the parallel cords in one layer cross those in the next layer at right angles. Reffner said that during the tire-building operation the sidewall rubber and tread stock are bonded to the rubber-impregnated fabric plies, usually with "some form of adhesive material." It is essential to the longevity of a tire that various components remain adhered to each other during operation. If not, they will move independently of one another and internal wear will result.
Reffner's opinion was that the blowout had been caused by a defect built into the tire at the time of its manufacture. He characterized this "incipient defect" as "either some void or failure to have proper adhesion." He based this view on the general nature of the failure and on the fact that the tread and other components of the tire were separated from one another, and all showed signs of abrasion. "The wearing is all internal so that the defect must have been internal." He testified, and the plaintiff's exhibits showed, that where the exterior sidewall and tread rubber had been torn away the cords in the fabric plies were frayed and broken. Little if any rubber remained on the surface of the exposed cords of the upper ply. Reffner interpreted this to mean that extensive rubbing together and breakdown of the tire components had occurred before the tread blew off and precipitated the accident. In his view, stresses built up at the location of a void or area of poor adhesion, causing its further growth and local heating. Eventually this internal wear broke the inner liner of rubber beneath the fabric plies, permitting air to push beneath the tread to form a bulge which ultimately ruptured, deflating the tire abruptly.
Reffner identified two operating conditions which could produce a similar failure sequence in non-defective tires: overloading and "gross" underinflation. The region where the ply cords broke is one of high stress and substantial flexing which either overloading or underinflation will augment. However, he found no sign of overloading, which he said is usually manifested by the appearance of cracks in the rubber of the tread grooves. The tread was unevenly worn, which to him did indicate some underinflated operation, but within a normal range, especially for a tire which had had ...