Claimants assert that due to the hilly nature of the highway, some of the melting snow/ice accumulated at the bottom of one of the hills, whereupon it froze that evening. It is Claimants' theory that their car hit the ice, and thereby crash. Based upon a thorough examination of all the evidence, the Court concludes that Claimants have failed to meet their burden of proof. Although both of the Claimants' complaints allege the existence of an ice patch, neither Claimant could testify to such at the hearing. Both Claimants failed to remember what caused the accident or whether there was ice on the road. When asked about the possibility that their head injuries interfered with their memories, both Claimants felt their memories were just as good as they had ever been. In fact, the testimony of almost every other witness indicates that there was neither ice nor water on the highway. about whether they passed a truck at the critical point in time. The Court concludes that Claimants have failed to prove that there was any ice or water on the road. (Schuette v. State (1984), 36 Ill. Ct. Cl. 61). Claimants cannot speculate as to the cause of their accident. (McCormick, 166 Ill. App. 3d 93, 519 N.E.2d 469, 116 Ill. Dec. 577.) In addition, Claimants cannot rely on the doctrine of res ipsa loquitur, as Respondent did not have "management and charge of Claimants' automobile at the time of the accident." Mavraganis v. State (1984), 36 Ill. Ct. Cl. 153. Even if there was an ice patch on the highway, there was sufficient evidence presented to establish that Claimant was the proximate cause of the accident, and not the Respondent. (Feldman v. State (1984), 36 Ill. Ct. Cl. 158.) the semi-truck driver indicated that Claimants were speeding when they passed, and that this was the cause of the accident.