Wash. Rev. Code § 4.24.770
(1) A private employer is not liable for any injury received by a third-party occupant of a vehicle that is owned, leased, or rented by the employer if, at the time the injuries were inflicted, the third-party occupant was riding in or on the vehicle with an employee who had explicitly acknowledged in writing the employer's policy on use of vehicles owned, leased, or rented by the employer and the third-party occupant was not:
[ 2011 c 82 s 3.]
Intent—Application—2011 c 82: See notes following RCW 4.92.180.
Definitions: RCW 52.12.160.