This paper was presented at session 36 - signing, delineation and guidance 1. Little attention has been given to the occurrence of polarisation of light reflected from road surfaces, signs and retro-reflective devices. However, the transmittance of windscreens is dependent upon the angle of incidence, particularly when the light is polarised. The luminance of objects seen through windscreens will therefore depend on the degree of polarisation of the reflected light and the angle of rake of the windscreen. Measurements have been made of road surfaces and pavement and button delineators to determine their polarising properties and the optical transmittance of windscreen glass as a function of incidence angle, and direction of polarisation. The results, including the formation of secondary images, are discussed in the context of current design and probable trends in car windscreen configurations. Mention is made also of windscreen transmittance at the longer wavelengths of light at which red traffic lights, etc. Operate. The number of the covering abstract of the conference is IRRD No. 239340.
Abstract