Is it me or does the radio stations synchronize their ad times?

Was listening to Red, Hitz, Fly, Mix and LiteRadio over the weekend, and found in many cases that their advertisement times are pretty much synchronized. Is there some "super" programme manager that synchronizes all the radio stations (at least the English Radio Stations) to get them to go "ad-air" all at the same time? It's damn hard to find a radio station playing music when the others are running ads. To me that's pathetic, having to listen to the same stale ads over and over again while driving and gnashing my teeth...