What is the test for determining whether a plaintiff is a plaintiff in a motor vehicle accident?

As this court stated in Stapiro v. Bookspan, 155 Cal.App.2d 353, at pages 357-358, 318 P.2d 123, at page 126: 'A passenger is one who gives compensation for a ride. [Citation.] Where the driver has received a tangible benefit, monetary or otherwise, which is a motivating influence for furnishing the transportation, compensation may be said to have been given, with the result that the rider is a passenger and the driver is liable to him for simple negligence. [Citation.] But whether the rider conferred a benefit or whether the ride was merely of a social nature is ordinarily a question of fact for the jury. [Citations.] It is only where the admitted facts can give rise to but one reasonable conclusion that the question of the rider's status becomes one of law. [Citation.]'