Louisville Metro Police traffic investigators are trying to determine how the driver lost control Wednesday morning of a AAA Rescue Ranger pick-up truck on Interstate 71, causing a chain-reaction that left the driver dead, police said.The AAA Rescue Ranger driver has not been identified.The accident happened at about 6 a.m. Wednesday and left northbound I-71 near the Watterson Expressway closed for hours, said Dwight Mitchell, a Louisville Metro Police spokesman. Traffic was moving on I-71 in the area by the early afternoon, according to TRIMARC.After losing control, the pick-up truck struck a wire barrier, flipped and came back into traffic -- it was struck by another pick-up truck, Mitchell said. The driver of the second pick-up was taken to University Hospital with injuries that did not appear to be life-threatening.The Louisville Metro Police Traffic Unit is investigating, Mitchell said.