Different authorities and organizations are committed to reducing road traffic accidents, deaths and serious injuries. More and more stringent regulations are being introduced. Car manufacturers continuously improve design of the vehicles, introducing various innovations. One of the basic preconditions for realizing road traffic safety initiatives is compliance with existing legislation. This particularly applies to the vehicle systems and components that have the most significant impact on road safety. Unfortunately, to improve visibility on older cars, many car users in Eastern European countries, including Latvia, choose a primitive but unauthorized solution: installation of non-certified high intensity discharge (HID) lamps into the headlamps, which are designed for halogen bulbs. The goal of the research is to determine the extent to which illuminance levels are exceeded if inappropriate and uncertified HID lamps are installed in the car headlamps of different designs. In the course of the experiments there were tested reflection and projection headlamps of various designs intended to use with H1, H4 and H7 category halogen lamps and mostly used together with non-compliant HID bulbs.