An accident in Clay County Tuesday afternoon that injured two people was caused by one of the drivers having a medical emergency. Trooper reports indicate Joey Walter, 27, of Independence was driving north on I-35 near Platte City when he had a seizure. Walter’s car smashed into the rear of the Mack truck being driven by Nicholas Brown, 30, of Quincy, Illinois. Both Joey Walter and his passenger Amanda Walter, 27, also of Independence, suffered minor injuries and they were taken to Liberty Hospital.