NEW ORLEANS (AP) — A 16-year-old boy driving relatives from Texas to a vacation in Disney World apparently fell asleep at the wheel, causing the sport utility vehicle to veer off the highway and roll over, killing three children and two adults, authorities said Thursday.

The teen, who had a driver's license but was not identified, was charged with reckless operation of a vehicle following the crash on Interstate 20 near Calhoun, Louisiana, at 11 p.m. Wednesday, said state police spokesman Michael Reichardt.

He and two additional passengers suffered minor injuries.

Authorities identified the adults killed as school teachers Michael and Trudi Hardman of Terrell, Texas. The children killed were ages 4, 7 and 15. Their names were not immediately released. None of those killed wore seat belts but the driver did, officials said. Reichardt said all the children in the vehicle were related to one another as siblings or half-siblings.

Michael Hardman was a second-grade teacher at an elementary school in Terrell, said Terrell Independent School District Superintendent Michael French. He had worked in the district for two years, French said.

"Our thoughts and prayers are with his family members, colleagues, students and friends," he said. "We must lift each other up during this difficult time."

French said a counselor contacted the parents of students in his class to let them know about his death, and counselors also are available to support both staff and students.

Trudi Hardman was a kindergarten teacher at the Wills Point Independent School District, the district said in a statement on its Facebook page. Telephone calls and messages left with the district were not immediately returned to The Associated Press.

The 16-year-old veered left onto the median and then tried to get back onto the highway but overcorrected, causing the 2005 Chevrolet Tahoe to roll over, police said. The drive from east Texas to Orlando, Florida, where Disney World is located, is about 1,050 miles — a 16-hour drive. Calhoun would have been about three-and-a-half hours into the drive, but it was not immediately clear when the family left their home, or how long they had been on the road Wednesday.

Six of the eight people in the SUV were thrown from the vehicle, police said. Ouachita Parish coroners pronounced the five family members dead on the scene.

"Our heartfelt condolences go out to all of the people affected by this tragic crash," said Col. Mike Edmonson, the Louisiana State Police superintendent. "In an instance this family vacation turned into an unspeakable tragedy."

Police don't believe the young driver was impaired, but a toxicology sample was taken, troopers said. The stretch of I-20 where the deadly crash took place is flat and straight and the weather was clear.