I think it depends on where you are in the timezone. On average, any place on the western edge of a timezone will have sunrise an hour later than the same latitude on the eastern edge. In the US, just in the eastern timezone, some towns in the upper peninsula of Michigan have sunrise 90 minutes later than eastern Maine, despite being in the same timezone, since the timezone boundaries aren’t perfect. But, the simple solution to having kids not go to school in the dark is just to have school start an hour later. If everything else is going to be an hour later to take advantage of the sunlight, school start times should just move forward, to take advantage of the sun (isn’t that the whole point of daylight savings?)