Low beam (dipped beam, passing beam, meeting beam) headlamps provide a distribution of light designed to provide forward and lateral illumination, with limits on light directed towards the eyes of other road users to control glare. This beam is intended for use whenever other vehicles are present ahead, whether oncoming or being overtaken.
The international ECE Regulations for filament headlamps and for high-intensity discharge headlamps specify a beam with a sharp, asymmetric cutoff preventing significant amounts of light from being cast into the eyes of drivers of preceding or oncoming cars.
High beam (main beam, driving beam, full beam) headlamps provide a bright, centre-weighted distribution of light with no particular control of light directed towards other road users’ eyes. As such, they are only suitable for use when alone on the road, as the glare they produce will dazzle other drivers.