A concept car developed by Japanese company Nissan1 has a breathalyzer-like detection system and other instruments that could help keep drunk or over tired drivers off the road.　　and passenger seats，while a detector in the gear-shift knob measures perspiration from the drivers palm.　　Nissans new concept vehicle also includes a dashboard-mounted camera that tracks a drivers alertness by monitoring their eyes.It will sound an alarm and issue a spoken warning in Japanese or English if it judges that the driver needs to pull over and rest3.　　The cars seat belt can also tighten if drowsiness is detected，while an external camera checks that the car is keeping to its lane properly. However，Doi admits that some of the technology，such as the alcohol odor sensor，should be improved.If you drink one beer，its going to register，so we need to study whats the appropriate level for the system to activate, he says.