## Facts

- Vernon Throop was driving west toward Tucson on U.S. Highway 80 in daylight on a straight, level roadway.
- Peter J. Hennen, a traveling salesman associated with F.E. Young & Co., was driving east on the same highway.
- Hennen’s vehicle suddenly crossed the center line into Throop’s lane, causing a head-on collision that killed both drivers.
- Throop’s widow sued Hennen’s estate for negligence and sued F.E. Young & Co. on a vicarious-liability theory.
- Evidence showed Hennen worked with substantial autonomy: no fixed hours, no in-office duties, self-selected routes and schedules, and infrequent office visits; the company did not direct how or when he drove.
- The specific reason Hennen crossed into the opposite lane was not established by direct evidence.

## Issues

1. Whether F.E. Young & Co. could be held vicariously liable for Hennen’s driving under respondeat superior based on a right to control the physical details of his work.
2. Whether res ipsa loquitur could be submitted to the jury against Hennen’s estate where the vehicle crossed the center line without a conclusive explanation.
3. Whether medical testimony from Hennen’s physicians was inadmissible under physician-patient privilege, or whether the privilege was waived.

## Decision

- The directed verdict for F.E. Young & Co. was affirmed because the evidence did not show the company controlled or had the right to control Hennen’s physical conduct in driving.
- The jury verdict against Hennen’s estate was affirmed; res ipsa loquitur was properly instructed and permitted an inference of negligence from the unexplained lane crossing.
- Admission of physician testimony and related medical evidence was affirmed because any physician-patient privilege was not preserved and was waived by defense conduct.

## Legal Principles

- Respondeat superior requires evidence that the employer controlled or had the right to control the physical details of the alleged servant’s work; general oversight or interest in results is insufficient.
- A traveling salesperson’s discretion over routes, timing, and methods, without employer direction over driving, can preclude vicarious liability as a matter of law.
- Res ipsa loquitur applies when (1) the type of event ordinarily does not occur without negligence, (2) the instrumentality was within the defendant’s exclusive control, (3) the plaintiff did not contribute, and (4) the specific cause is uncertain; the doctrine permits, but does not compel, an inference of negligence.
- Physician-patient privilege may be waived by failure to timely assert it and by voluntary use or introduction of medical information inconsistent with maintaining confidentiality.

## Conclusion

The court held that an employer is not liable for a traveling salesperson’s driving absent a right of control over the physical details of that conduct, that an unexplained crossing into oncoming traffic on a straight road supports a res ipsa inference for the jury, and that physician-patient privilege objections can be lost through nonassertion and litigation conduct amounting to waiver.


Throop v. F.E. Young & Co., 94 Ariz. 146, 382 P.2d 560 (Ariz. 1963)