WASHINGTON – The region’s largest school district returns to class Tuesday morning with a schedule change that could impact traffic.

Most Fairfax County Public High Schools will start the day at 8:10 a.m. this school year, almost an hour later than last year.

FCPS decided to shift the schedule in response to research from the American Academy of Pediatrics.

It found improved outcomes when bell schedules more closely correspond with biological sleep rhythms of adolescents.

The outworking of the schedule change remains a question.

Buses and parents will be chauffeuring students to class when many commuters are heading to work.

District wide, FCPS uses more than 1,600 buses. Enrollment is estimated at 188,545.