Various governmental and non-governmental organizations are committed to taking steps to reduce road accidents, deaths and serious injuries. Many countries around the world have adopted Vision Zero, an initiative started by Sweden to promote road safety, whose motto is: no loss of life is acceptable. More and more strict regulations are introduced, the world's car manufacturers introduce more and more new safety systems and innovations. In the dark time of the day, road safety is largely influenced by road lighting provided by headlights. The lighting of the headlights also depends on the voltage value of the car's electrical system. The voltage of the electrical system is chosen according to the climatic conditions, and this voltage varies from vehicle to vehicle. The purpose of this study is to find out to what extent road lighting is affected by the value of the voltage maintained by the car's power supply system.