An active shooter situation is when an unknown person comes into a building and starts shooting.

"There was particular emphasis placed on active shooter response after the Columbine incident in Littleton several years ago."

Lt. Dan Davis with the Sacramento State police department says their emergency training is always being upgraded. 

"We go through extensive scenario-based training on a regular basis."  

UC Davis officials say they’re currently looking at ways to improve their emergency notification system by sending messages out via e-mail and cell phones.

Meantime, campus police chief Annette Spicuzza says the Virginia Tech incident hasn’t spurred any heightened security. 

"We’re just doing business as usual. Always looking back to see how is it that we may be able to do things better." 

And at the Los Rios Community College District, spokeswoman Susie Williams says security is always tight on their four campuses. 

"These kind of things are always very horrible and we do our best to hope that they don’t happen here in Sacramento but they certainly could."

Security experts say even the best trained officers can’t be everywhere all the time.