Nissan is using technology to boos safety in its cars. They invented three systems to reduce risks of drunken driving. A system measures the amount of alcohol in a person's perspiration, and if it is higher than the allowed limit, the car refuses to move on. In another system, they check eye movements, and if the driver is drowsy, then the seat belt snaps tight, in an attempt to wake up the driver. In the third system, the car monitors whether it is moving in a straight line or is waivering about.