Citation

Clark BAJ. Aust. Road Res. 1969; 4(1): 22-34.

Copyright

(Copyright © 1969, Australian Road Research Board ARRB)

DOI

unavailable

PMID

unavailable

Abstract

It is shown that 'phantom' intensities in traffic control signals can be successfully predicted from laboratory measurements. An artificial 'Sun' was used to illuminate the signal head and the intensity ratio of colored to white sun phantom was measured. The white phantom found in practice can be calculated from the known luminance of the Sun and from the signal refractor geometry, so that colored phantom intensity can then be calculated. Methods for control of signal phantom.