PARIS — A car laden with travelers careened off one of France's busiest highways in smoke and flames, killing five children and injuring the four other people aboard as it barrel-rolled in a fiery wreck.

The vehicle was carrying nine people, all members of the same family, on Monday evening when it started to spew smoke and caught fire, seemingly sparked by an as-yet-undetermined technical problem, authorities said.

The driver lost control and the vehicle rolled repeatedly to finish in a crushed, blazing heap in a field next to the A7 highway, also known as "the Highway of the Sun," cutting south through the Rhone valley from Lyon to the Mediterranean port city of Marseille.

The family had been heading back to their home on the outskirts of Lyon, authorities said. The injured — three adults and a child —were evacuated to Lyon hospitals.