Even if we assume, for the sake of argument, that the speed of the plaintiff should, as a matter of law, be considered a condition and not a cause, in light of the totality of circumstances in evidence, the plaintiff's requested charge would effectively usurp the function of the jury by precluding from their consideration evidence relating to the plaintiff's failure to maintain a proper lookout and his failure to apply brakes. This is not a case where the facts require a conclusion by the jury that the defendant's acts were the sole proximate cause of the plaintiff's injuries; DePalma v. Cappella, 157 Conn. 139, 141-42, 249 A.2d 235 (1968); nor can we conclude that the plaintiff's actions were so far removed from "the actual occurrence producing the injury that they become mere `incidents of the operating cause.'" Kinderavich v. Palmer, 127 Conn. 85, 93, 15 A.2d 83 (1940).