In Phoenixville, the Jan. 17 vote to start high school and middle school at 8:05 in the 2019-20 academic year — from 7:24 and 7:28, respectively, now — was the culmination of 18 months of study by a task force of district stakeholders. School will end 40 minutes later, at 3 p.m., with a few minutes squeezed from the school day. The group weighed disruption and likely higher costs for bus transportation and day-care issues against the growing body of science that teens are hard-wired to wake up later.