Do radio stations make agreements to synchronize their commercial breaks?

Usually when I am listening to my car radio, I will punch another preset if a station goes to a commercial. Often, this station will also be on a commercial break. So I punch another with the same result. This got me wondering if radio stations in urban areas sometimes agree to have commercial breaks at the same time in order to increase likelihood of their listeners remaining on their station.
By the way, this isn’t normally on the hour or the half hour. It occurs at seemingly random times, and almost every time.