In what circumstances will an employer be liable for injuries sustained by an employee in a motor vehicle accident?

In Rodgers v. Kemper Constr. Co. (1975) 50 Cal.App.3d 608 at pages 618-619, 124 Cal.Rptr. 143, the court stated: "California has adopted the rationale that the employer's liability should extend beyond his actual or possible control over the employees to include risks inherent in or created by the enterprise because he, rather than the innocent injured party, is best able to spread the risk through prices, rates or liability insurance....