I went to several schools and kids being driven to school has always been an exception. They mostly walked or took public transport [0]. My sister went to high-school in a more rural area (read far-away suburb) and kids from the surrounding towns used to take the school bus.
Yet, school still started very early, a little past 8:00 AM. I absolutely loathed having to get up so early in the morning (7-ish) and used to be half asleep for the first few periods.
While US issues around transportation certainly don't help, there must be something else going on with the school schedules since they seem to be roughly the same in areas where transportation is not an issue.
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[0] I know there were exceptions for kids living far away, I was one of them since we moved during high-school, but I didn't change schools. However, this is absolutely not the norm where I grew up.