Cars windows made from 'liquid' glass could be used as screens for localized targeted information and advertising, according to an Israeli start-up.Technology company Gauzy worked with German carmaker Daimler Benz to develop its opaque screens. It debuted the smart glass at the Autobhan Expo Day in Stuttgart in February.Gauzy developed a method to bond sheets of flexible plastic material containing a liquid crystal layer to car windows which become clear when an electric current is passed through them, but are opaque without it.The company aims to use its technology for smart messaging based on where the car is parked and local conditions."That [technology] can let passers-by know of nearby attractions, give you a lot of information...that is related and relevant to the location the car is at," explained Gauzy CEO, Eyal Peso.The car is transformed into a video display unit that includes the opaque glass windows, a projector, and a controller that connects to the internet to help determine the location of the car and download and display relevant footage and images in high definition quality.The display mode is activated only after the car has been parked and the engine has been switched off."Our technology allows the window to be transparent, you need it to be transparent while you're driving," Peso said.Gauzy plans to install the glass only on side and rear windows.The technology to change the state of glass from clear to opaque is not new and has been used for several years in shop advertising and in luxury hotel,s but it has never been used before in a road vehicle, Peso said."Our vision for the technology as a display on a car window is vast," he added. "Think of a car that is no longer only a car but is a medium to present information," he added.Although Gauzy's technology is fully developed, the smart glass advertising windows won't be seen on cars for a few years yet.The company expects the displays to be subject to regulations to prevent distractions to passing drivers, as well as advertising rules.