Across the United States, what has been names as “Lockdown Generation” elementary to high schoolers are learning how to hide and protect themselves against attacks in the school. With the drastic increase of school shootings since Columbine, new procedures have been implemented in order to keep the students safe. WSTP reported “From 1999-2015 the number of students who said school doors were locked during class jumped from 38% to 78%. In 1999, the same year as the shooting at Columbine, 19% of schools reported using security cameras. By the 2013-2014 school year, 75% of schools had cameras installed.”
After the shooting in Parkland, Florida 2018, the News and Observer reported: North Carolina proposed for schools to employ more police officers and mental-health specialist in schools, and improving building security and teaching students about civic responsibility. Later that same year when the students was shot at Butler High School in Mathews, Charlotte-Mecklenburg started more security screens, such random gun searches.
According for ADT lock downs are required for situations that include: Active shooting, hostage situation, riots, nearby police activity, and national disasters. When the lock down are called for the teachers and other staff are required to:
Lock and never open windows and doors
Turn off all lights
Close blinds and or curtains
Instruct the students to stay low and away from windows
Keep everyone inside the classroom
Silence all electronics such as cellphones, and TVs
Clear hallways, bathrooms, or other areas that can not be secured
Remain inside until the all clear has passed

https://www.adt.com/resources/school-lockdown-procedures
https://www.wtsp.com/article/news/education/heres-how-much-school-security-has-changed-increased-over-the-past-20-years/67-585889537
https://www.newsobserver.com/news/politics-government/article226925124.html