Recently the interest in autonomous vehicles increases a lot, many studies are made and the researchers investigate the relationship between automatic vehicles and human being. Those studies focus on the relationship between autonomous vehicles and pedestrians or the drivers and the autonomous vehicle. In fact the presence of autonomous vehicle on the road is reality in some country, and it is fundamental to know how we can improve their efficiency. What we actually want to study is the relationship between the autonomous vehicles and the manned vehicles, since it is unlikely that since the beginning the autonomous vehicles will be the only ones on the streets.