Here’s a cool privacy feature on the new monorail train in Daegu, South Korea; windows that automatically fog when passing apartments that are close to the train. The technology is known as Smart glass and the glazing occurs when the window’s light transmission properties are altered through the application of voltage, light or heat to the surface.

 

 

The technology also appears on select trains in Singapore and has applications in office spaces, meeting rooms and other areas that may not require privacy at all times. You can see the ‘privacy’ glass enabled below along with a couple embedded videos demonstrating the technology.

[via is4ac on reddit]