Examination of the vehicle light intensity in terms of road traffic safety: a case study

Road transport is an essential part of modern life. It brings with itself, besides the desired effects, negative aspects as well. Negative aspect is not only the emissions production but also the traffic accidents occurrence even with tragic consequences. In proportion to traffic intensity, accidents during decreased visibility represent a significant share. A driver has a limited source of information at this time, since only vehicle headlights illuminate the runway and its surroundings. However, these do not only illuminate the roadway ahead of the vehicle, but part of the emitted light also falls into the drivers’ eyes of vehicles in the opposite direction. Thus, the eyes of such glared drivers worse recognize details, or lose the ability to see at all, i.e. vision ability. The level of vision loss depends on the light intensity that falls into the drivers’ eyes in the opposite direction. This light intensity is related not only to the correct headlights alignment (setting) but also to their design. In this paper, three generations of headlights in terms of the light intensity falling into the driver’s eyes of the vehicle in the opposite direction are compared. The headlights alignment of the examined vehicles was checked prior to measurements in accordance with the manufacturer's requirements. Given the fact that intensity of the emitted light is also related to the age of the used source, they have been replaced by the new ones. For the reason of objectivity, examination was performed at night at the New Moon phase, thus it did not light up. The starlight also did not affect the measurement results because it was cloudy, but it did not rain. There were no artificial sources of light near the measuring point.