Maywald v. Toyota Motor Corp., No. CV-25-0009-PR (July 7, 2026) (J. Beene)https://www.azcourts.gov/Portals/0/OpinionFiles/Supreme/2026/CV250009PR.pdf?ver=-DHMOy60U_mvlq9EoXdIxw%3d%3d

ABSENCE OF LANE DEPARTURE WARNING SYSTEM IN AUTO DOES NOT EXCUSE DRIVER FROM DRIVING UNSAFELY AND DOES NOT RENDER AUTO DEFECTIVE/TO PROVE STRICT PRODUCTS LIABILITY PLAINTIFF MUST FIRST PROVE PRODUCT IS DEFECTIVE AND THEN THAT IS UNREASONABLY DANGEROUS/APPLICATION OF CONSUMER EXPECTATION TEST & RISK BENEFIT ANALYSIS

Plaintiffs were injured in an auto collision when the adverse driver fell asleep allowing his auto to drift across the center line and collide with plaintiffs' auto. Plaintiffs sued Toyota Motor Corp [Toyota] alleging strict products liability for not having installed a lane departure warning [LWD] system technology in the adverse driver's auto which allegedly would have awoke the adverse driver to the impending collision and prevented the collision. 

The Navajo County Superior court granted Toyota's motion for summary judgment. Plaintiffs appealed and the Arizona Court of Appeals vacated the judgment and remanded the case for further consideration. The Arizona Supreme Court vacated the court of appeals decision and affirmed the trial court.

First the Supreme Court held that a plantiff in a strict products liability case must first prove the product is defective and then that the defect rendered the product unreasonably dangerous and these are distinct and separate elements of the tort. To the extent our courts have blurred the distinction between these two elements (see, e.g., Dart v. Wiebe Mfg., Inc., 147 Ariz. 242 (1985)) they are "disapproved."

As stated in Readenour v.Marion Power Shovel, 

149 Ariz. 442, 447 (1986)proof of a defect alone is

insufficient to establish liability. 149 Ariz. 442, 447 (1986)

defect” is distinct from an “unreasonable danger.” 

that a product is “defective” or in a “defective condition” when it is “unsafe

for ‘normal handling and consumption.'” Id. at 447 (quoting Restatement

§ 402A cmt. h); see also Bailey v. Montgomery Ward & Co., 6 Ariz. App. 213,

218 (1967) (defining a “defective article” as a product “that is not reasonably

fit for the ordinary purposes for which such articles are sold and used”

(citation modified).

By contrast, a product is “unreasonably dangerous” when it

is “more dangerous than a consumer would expect or whose risks outweigh

its benefits.” Readenour, 149 Ariz. at 447. In Readenour, this Court

reaffirmed that proof of defectiveness alone is insufficient to establish strict

product liability. Such liability arises only when the defective condition

also renders the product unreasonably dangerous. Preserving this

distinction provides parties and courts with a more defined analytical

framework for determining when a defective product gives rise to strict

product liability

To determine if a product is unreasonably dangerous, the court applies two tests: the consumer expectation test--"product fails to perform as safely as an ordinary consumer would expect when used in an intended or reasonable manner" and when  a consumer could not know what to expect, as in many design defect cases, the risk/benefit analysis where the court considers this non-exclusive list of factors:

(1) The usefulness and desirability of the product,

(2) the availability of other and safer products to meet the

same need,

(3) the likelihood of injury and its probable seriousness,

(4) the obviousness of the danger,

(5) common knowledge and normal public expectation of the

danger (particularly for established products),

(6) the avoidability of injury by care in use of the product

(including the effect of instructions or warnings), and

(7) the ability to eliminate the danger without seriously

impairing the usefulness of the product or making it unduly

expensive.

The Supreme Court concluded on the facts of this case, reasonable consumer expectations are that an auto will be designed to allow the driver to drive the auto within marked lanes. A product is defective if it is "unsafe for normal handling and consumption."There is an expectation that safety devices will guard against injury by accidents. But there is no expectation that a vehicle will prevent human error in careless driving. Although LDW technology may enhance vehicle safety, it does not eliminate the driver's fundamental responsibility to maintain control of the vehicle. Nor can it reasonably be disputed that an ordinary driver understands the obligation to stay awake and remain within the proper lane of travel and appreciates the inherent danger of crossing into a lane occupied by oncoming traffic." See A.R.S. Sec.28-729(1).

As such the court held that the absence of LDW technology did not render the Toyota defective.  Absent a finding of a defect there is no need to do an analysis regarding whether the product was "unreasonably dangerous" and the court of appeals erred in applying the risk/benefit analysis here where it focused upon Toyota's ability to design a safer auto rather than "whether the risks inherent in the challenged design--the 4Runner as sold without LDW technology--outweighed its benefits."