Under contract with the dienst verkeerskunde of the rijkswaterstaat (ministry of transport) several studies are being carried out with regard to the perceptibility of traffic and road signs at night. Evaluation of (1) the effectiveness of a new type of retroreflective material and (2) the necessity of external illumination of signs are elements of these studies. Questions such as these can only be answered adequately when knowledge is available on the intensity of the headlamps of dutch cars. As there was no previous information on this, some field measurements were carried out. The 85th percentile intensity levels were derived from the resulting data.
Abstract