Motion sensor lights in the hallway

[Freeman Schultz]

I am watching an episode of "The Office" where Dwight now owns the building that the Scranton branch of Dunder Mifflin. One of the running jokes is that Dwight has installed motion sensor lights in the the office in order to cut down on electricity. Every time the lights shut off, everyone has to wave their arms and jump up and down to activate them. I know that self storage facilities install them in their hallways and in some office buildings they install them in their restrooms. I am wondering has anyone installed in their hallways and does it really cut down on electricity costs?