Police are concerned about the safety of motorists in Saugeen First Nation.
Bruce Peninsula OPP say people are throwing apples and rocks at vehicles along Highway 21 and other roads in that area.
While no one has been injured to date, there is the potential for a serious injury.
Police say a motorist could lose control of his/her vehicle, be struck by breaking glass or be struck by the object itself via an open window.
Since the middle of summer, police have received seventeen complaints about this type of incident.
The most recent took place today when a passing vehicle was struck by a stone.
Police are urging anyone with information about these incidents to call OPP or Crime Stoppers.