ORLANDO, Fla. -- Four people were killed when a truck veered out of control on the Florida's Turnpike in Osceola County, crossed a 33-foot grassy median and struck two vehicles heading in the other direction, officials said.

Officials said the crash occurred on the Turnpike at the 227-mile marker in Osceola County, near the city of Kenansville.

Jerry Mann, 60, of Shady Dale, Ga., was driving the 2000 Chevrolet 1500 in the southbound lane when he lost control, and hit the back of a Ford Explorer and front of a Lincoln Continental heading the other direction, authorities said.

All four people in the Lincoln died.

The 88-year-old driver, and his 81-year-old wife died at the scene. Two backseat passengers, an 81-year-old woman and her 82-year-old husband, were taken to local hospitals, where they died.

None of the victims' names were released.

Mann was thrown from his truck, and was in critical condition at Orlando Regional Medical Center Sunday night, officials said. His passenger, Clarence Tippett, 68, of Newbern, N.C., suffered minor injuries.

The two men were traveling to Miami, where they planned to catch a flight to Haiti on a church mission to help build a schoolhouse, said Jean Hargreaves, a friend of Mann's family.

The Explorer's driver, Harry Robinson, 64, of Coconut Grove, was not injured.

Heavy rain and speed could have been factors in the crash, said Florida Highway Patrol Trooper Kim Miller.