system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do radio stations seem to all go to commercials at the same time?

Where I live (Orlando) all of the popular stations seem to go to commercial break at the same time. This is especially noticeable in the morning during my commute.
gpt
These answers are mostly wrong.  Arbitoron has always been the primary source for radio ratings.  They base their ratings on feedback from designated listeners who keep diaries of which stations they listen to throughout the day.  They log their listening activity every quarter-hour (on the hour, :15 after, :30 after, and :45 after).  So stations always want to have programming (music, talk, whatever) at those times.  It is very bad form to have a commercial break that runs over the quarter hour.  So consequentially, commercials are clustered during the rest of the hour.