Lear Siegler, Inc. v. Perez, 819 S.W.2d 470, 472 (Tex. 1991) is an example of product manufacturer`s liability for death in a car accident case. Perez, an employee of the Texas Highway Department, was driving a truck pulling a flashing arrow sign behind a highway sweeping operation. 819 S.W.2d at 471. The sign was used to warn traffic of the highway maintenance. See id. The sign malfunctioned when wires connecting it to the generator became loose, as they had the day before. See id. Perez got out of the truck to reattach the wires. See id. As Perez worked, an oncoming vehicle, whose driver was asleep, struck the sign which, in turn, struck and killed Perez. See id. Perez's survivors sued the manufacturer of the sign. See id. Based on the facts of the case, the supreme court held the connection between the defendant's conduct, manufacturing a defective sign, was too attenuated to constitute the legal cause of Perez's death. See id. at 472. The fact that "but for" the malfunction, Perez would not have been at the place where the accident occurred, was insufficient to establish cause in fact. See id. Section 431 of the Restatement (Second) of Torts is instructive on the issue of legal causation: In order to be a legal cause of another's harm, it is not enough that the harm would not have occurred had the actor not been negligent. . . . the negligence must also be a substantial factor in bringing about the plaintiff's harm. the word "substantial" is used to denote the fact that the defendant's conduct has such an effect in producing the harm as to lead reasonable men to regard it as a cause, using that word in the popular sense, in which there always lurks the idea of responsibility, rather than in the so-called "philosophic sense," which includes every one of the great number of events without which any happening would not have occurred. RESTATEMENT (SECOND) TORTS 431 cmt. a (1965).