The Cost of Carelessness is a precursor to those infamous traffic-safety films that traumatized generations of American students. It was commissioned by the Brooklyn Rapid Transit Company as part of a campaign to reduce accidents involving trolley cars. As urban densities increased (Brooklyn’s population had doubled since 1890 to almost 1.7 million), there was a growing sense that city streets were fraught with perils. Such fears were not without reason. In 1913, Brooklyn had on average 30 violent accidents each day involving trolleys. The transit company responded with a “Safety Crusade” which brought lecturers—and films—to schools. The Cost of Carelessness may be the earliest film to depict a film being shown in a classroom.