We do have "Bikie Gangs" here, such as the Hells Angels, Comancheros, Black Ulans and others and they are involved in crimes such as drug dealing, extortion, stand over tactics and the like but generally don't bother the public.
Most of their activities involve other gangs or the underworld. Occassionally they will try to murder a member of another gang and less often succeed.
Bad behaviour on the roads is mostly done by "stupid" individuals.