Well, hoons are all the things I mentioned in a previous post, but yes, they are mainly hooligans in cars that drive round and terrorise the neighbourhood. Wikipedia entry on Hoons

We live near a roundabout on a long wide street, and every weekend the hoons come out. You can hear them screaming up and down the streets and "chucking wheelies" at the roundabout, but it's no use calling the police because if they bother to come at all, it's much too late and the hoons are long gone.

As for playing loud music like Barry Manilow, I can't see how that would stop them, because it would be drowned out by the loud music in their own cars, and of course in our case, and in most cases, they are not in a car park, but driving up and down the street. Or should the whole city be wired for sound? Nah, it'll never catch on, teddy (obscure reference to an old TV commercial).