Mayor Bill de Blasio on Thursday signed a new school safety law named after Avonte Oquendo.
Avonte is the teenager with autism who ran out of his school last October and was found dead in the East River in January.
The law puts a focus on exterior door alarms that could prevent students from leaving school unnoticed.
It requires the Department of Education to evaluate the need for alarms on all elementary schools by May 30, 2015 and come up with a timeline for installing them.
"It was a time that the whole city joined together in that search. The whole city felt the pain of his loss, and it was a moment that crystallized for all of us, especially those of us that are parents, but really all of us, the need to do something to additionally protect our children."
The law also applies to all schools in District 75 that serve kids with special needs.