Classes taught by police departments and others are extremely popular across America.
Classes where students learn how to survive an active shooter situation are drawing big crowds all across America.
Already increasingly common in schools and other institutions, training sessions about how to survive such attacks are now a hit with the general public.
The Associated Press reports that the popularity these sessions, many of them held by sheriff's offices or other police agency, has skyrocketed since the December shooting in San Bernardino that killed 14.
So-called "awareness trainings" have been held by police in Livonia, Michigan, Douglasville, Georgia and Amarillo, Texas, among others.
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The Amarillo class, taught by the Potter County Sheriff's Office, has been attended by over 600 people.
The Amarillo class follows the CRASE curriculum, which stands for Civilian Response to Active Shooter Events and follows basic tenets shortened to ADD: "Avoid" the situation by getting out, "Deny" by barricading inside a room, and as a last resort, "Defend" by fighting back.
HOW ARE THESE TIPS PUT INTO ACTION?
Following the horrific Umpqua Community College massacre in Oregon on Oct. 1, security expert Bill Stanton told INSIDE EDITION that using furniture to make a barricade can keep a gunman out of a classroom.
The Los Angeles County Sheriff's Department produced a graphic training video of a shooting on a college campus - along with tips on how to survive.
“Use cover, something that will stop a bullet and concealment, something that will at least keep you out of sight!” said the video.
Stanton added that if there is a chance to escape - take it. Running in a zig-zag pattern also makes you a difficult target to hit.
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But what if the gunman gets into the classroom - as Chris Harper Mercer did? This is the worst-case scenario because you're in an enclosed area.
Our security expert said to use every available weapon – bags, furniture and even fists to overpower the gunman.
“It really does need to be a group effort. I can either run to the back of the class and be a target, or I can fight for my life,” he said. “And the more people engaged in that fight, the better chance everyone has to survive.”
Watch Below: Witnesses Say Oregon College Gunman Asked Students Their Religions
