2009 Planning > Regional Programs > Studies > Completed Studies > 2009 > Quiet Zone Designation in New Jersey: An Informational Guide Print Quiet Zone Designation in New Jersey: An Informational Guide The federal requirement that train horns be sounded at every grade crossing in or near communities nationwide has sparked a number of questions with regard to the establishment of quiet zones. The North Jersey Transportation Planning Authority (NJTPA), as northern and central New Jersey's Metropolitan Planning Organization (MPO), has put together an informational quiet zone brochure as a guide to communities throughout the state.