Schools around the U.S. are looking for ways to impose tougher security measures in the wake of last month's school shooting in Florida that left 17 people dead.
And they don't have to look further than urban districts such as Detroit, Chicago, Los Angeles and New York that installed metal detectors and other security in the 1980s and 1990s to combat gang and drug violence.
Security experts believe these measures have made urban districts less prone to mass shootings, which have mostly occurred in suburban and rural districts.
National African American Gun Association president Philip Smith says security measures at urban schools are "eons ahead" of those in the suburbs because "they've been dealing with violence a lot longer."
