A toddler riding in the sleeper compartment of a big-rig truck opened the hatch and fell to his death on the freeway as his father drove on another 10 miles before noticing he was missing, authorities said Friday.

The Folsom, Calif., trucker was driving southbound Thursday night on the Golden State Freeway when his 2-year-old son apparently awoke and unlatched the compartment's spring-loaded hatch, California Highway Patrol Officer Scott Ellis said.The boy tumbled onto the freeway near an interchange with the San Bernardino Freeway, police said.

The father, whose name was withheld until the child's mother could be notified, continued driving down the freeway, unaware of the accident.