Insurance — Uninsured motorist — Phantom vehicle — Plaintiff did not improperly stack inferences to show that the negligence of the driver of a pickup truck from which a ladder fell onto the roadway on a bridge was the cause of accident resulting from the ladder being on the roadway — Inference that ladder fell on roadway from phantom vehicle was established to exclusion of all other reasonable inferences — Further inference that owner of vehicle was negligent in failing to properly secure ladder was reasonable and permissible — Trial court properly denied insurer’s motion for directed verdict which alleged that plaintiff improperly stacked inferences