Not to bring up anything, but I believe I remember someone saying (my father's a policeman, but I can't remember if he told me or if it was from another source), that a good portion of motorcycle policeman are viewed almost as public relations positions. And I remember them saying that they don't wear gear so they can smile and wave at the locals and whatnot.
Certainly the bike offers distinct advantages over a car when chasing, pulling over, or responding to certain crimes. However I personally have never seen a motorcycle cop doing anything that a car unit couldn't be doing.
BUT, the motorcycle cops are seen, can be talked to, and you can put a face to a policeman rather than just seeing a car. So it may make police stations look nicer, safer, more "for the people". Especially when you see them in parades, leading processions, etc. Kinda like a mounted (horse) cop. Yes, the horse is trained to pin a person against the wall at command, yes the horse can run in parks and trails after someone where a vehicle can't, but they mounted police seem to be more of a public relations thing. In parades, giving directions, photos, that sorta stuff. BUT, they can and will respond to a call if needed.
Alexi
PS - The Public Relations line have any merit? I can see it....but I don't know if that's a part of it.