What is the test for contributory negligence in a motor vehicle accident where a plaintiff falls asleep at the wheel?

The trial court had found, however, that the plaintiff knew that the driver was intoxicated at the time he commenced to drive, and with such knowledge of the driver's intoxication the plaintiff went to sleep. (See also Davis v. Nelson, 221 Cal.App.2d 62, 67, 34 Cal.Rptr. 201.)

In Enos v. Montoya, 158 Cal.App.2d 394, 322 P.2d 472, the plaintiff had fallen asleep after having been at a beach party with the driver and others, where the driver consumed beer and the plaintiff also had been drinking beer. The test there was held to be whether the plaintiff knew or should have known that the driver was intoxicated. A refusal to instruct on contributory negligence was approved, and a judgment in favor of the plaintiff-guest was affirmed.