A guest passenger cannot recover under both the liability and UM coverages of the host driver’s insurance policy when the negligence of the host driver is the sole cause of the accident. Nall v. State Farm Mut. Auto. Ins. Co., 406 So.2d 216 (La. 1981).
However, if the guest passenger is injured as a result of the joint negligence of the host driver and of another underinsured motorist, the guest passenger may recover under the liability coverage of the host driver’s policy for the host driver’s negligence, and may recovery under the UM coverage of the host driver’s insurance policy for the negligence of the other underinsured motorist. Casson v. Dairyland Ins. Co., 400 So.2d 713 (La.App. 3d Cir. 1981).