Investigators learned the unidentified man was driving a silver Dodge Ram in the 12400 block of Sam Houston Parkway around 4:51 a.m. when he failed to control his speed, causing him to veer out of his lane and crash into a concrete barrier, said Houston Police Department spokesman Victor Senties. The man was not wearing a seat belt and was thrown from the truck into a bayou about 20 feet below the roadway, Senties said.