Abstract
By studying the distribution of the light intensity capacity in the neightbourhood of the axes of the high beam headlights and admitting that the illumination of the obstacles should be 2 lux, it is shown that the sum of the axial beam intensities of all headlights must be 300.000 candela in order to assure the visibility on a straight road up to about 600 metres. That such an intensity is acceptable has been deducted from tests carried out which determined at which moment the drivers coming from the opposite direction request the change from high beam to dipped beam. The problem raised by sudden change from very intense high beams to dipped beams could be solved by an electronic control device.