NEW YORK (CBSNewYork/AP) — Officials are installing 21,000 audible door alarms at New York City schools in order to prevent another tragedy like the 2013 disappearance of an autistic student.

Department of Education officials said Thursday that the alarms will all be in place by the end of the year, WCBS 880’s Rich Lamb reports.

READ MORE: Protesters Attempt To Storm Entrance Of Barclays Center Over Nets' Refusal To Allow Kyrie Irving To Play Due To NYC Vaccine Mandate

Avonte Oquendo, 14, slipped out of his Queens school in October 2013 and was later found dead.

Since then, council member Robert Cornegy and father of six has waged a one man battle to alarm school doors.

READ MORE: NYPD: Knife Fight Spills Into Midtown Pizzeria, 2 Taken Into Custody

“97 percent of principals across the city requested that alarms be installed in their buildings,” Cornegy said.

Finally, last year, the City Council passed a bill called Avonte’s Law. It requires the Department of Education to survey all schools and evaluate the need for safety measures including audible alarms.

Deputy Schools Chancellor Elizabeth Rose said 97 percent of city schools requested the door alarms. The others either already had them or lease space in buildings with their own security systems.

“We are on track to install door alarms at nearly 100 percent of our schools by the end of 2015,” Rose said.

MORE NEWS: With Less Than A Week Before NYC's Deadline, Municipal Workers Hold Anti-Vaccine Mandate Rally On Staten Island

(TM and © Copyright 2015 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2015 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)