Illumination of head lights of vehicles, such as automobiles, trucks and motorcycles, is a vital safety aspect, especially when driving in dark conditions. The main purpose of the illumination is to illuminate an area in front of the vehicle. Another advantage of the illumination is that it facilitates detection of the vehicle. When driving in dark conditions, head lights having a high beam mode are a solution to increase the illumination and widen the area being illuminated by the head lights. The vehicle driving safety in dark conditions is significantly increased when driving with the head lights in high beam mode, due to an increased visibility of the area in front of the vehicle. However, due to risk of dazzling oncoming traffic it must be turned off in many driving situations. When turned off under dark conditions, the risk of collision is significantly increased. Some of today's vehicles are provided with an automatic head light control unit that turns on a high beam mode when judged not to risk a dazzling of oncoming traffic and turn off the head beam mode when judged a risk of dazzling. Such a unit is associated with the drawback of it not being assured that drivers use the unit at all time. Therefore, there is a need for a solution which can increase the safety of driving, especially under dark conditions.