A recent statement from the AASM (American Academy of Sleep Medicine, a group of 10,000 scientists and health experts) wrote that moving high school start times to after 8:30am would have a massive effect on the high school population and offer a range of health benefits. In most cases, there would need to be some new arrangements of bus routes, school schedules, and pick-up times, since many families rely on their high-school aged students to watch younger family members until a parent gets back home from work. But I think that the benefits for the high-school population are worth pushing for in this instance.
According to the CDC (Center for Disease Control and Prevention) about 70% of high school students report getting seven or less hours of sleep per night compared to the 8-10 hours that are recommended by doctors. This sleep deprivation can have harsh side effects ranging from sleepiness at the wheel, loss of attentiveness, lower school performance rates, obesity, increased risk-behaviors, phsyical accidents in sports, and higher depression rates and instensified symptoms. Another study showed that changing the school hours decreased car accidents caused by drowsy teenagers by 16.5% in the two years after the school district made the change compared to the two years prior to the change.
But the real issue is the conflict between the school system's cycle and the teenager's cycle. During the teenage years, a person's brain produces melatonin (a natural sleep inducer) at a different time than in childhood or adulthood. For the most part, teenagers actually phsycially aren't tired until around 11:00pm at least, making that 5:00-6:00am wakeup time a real issue for their sleep schedule. The statement also made it a point to recognize that changing the school system won't be enough unless parents and teenagers value sleep more and encourage regular sleep-wake cycles and decreased technology use before bedtime, which means that better sleep education might be neccesary as well!