California ? A charter bus traveling on a Mojave Desert freeway flipped on its side Saturday morning in Ludlow, Calif., killing a woman and injuring 22 other people, authorities said.

The bus was the only vehicle involved in the wreck on Interstate 40, about 115 miles southwest of Las Vegas, said San Bernardino County Fire Department spokeswoman Tracey Martinez.

“It did not roll over but it did land on its side,” she said.

Witnesses said the bus drifted across lanes and into the median, Officer Taj Johnson of the California Highway Patrol said.