Mayor de Blasio signed legislation dubbed "Avonte's Law" Thursday aimed at making schools safer for students with special needs.
The new law requires that the Department of Education evaluate the need for alarms on all exterior doors at elementary schools and those serving students with special needs.
If it is deemed that a child can open a door, an alarm must be installed.
The bill known as Avonte's Law was inspired by the disappearance of 14-year-old Avonte Oquendo from his school in Queens last October.
His disappearance in October set off an extensive search. The autistic teenager's body was found in January along the East River.
The city medical examiner ruled that the boy's cause of death could not be determined.