Citation

Garner LF, Vingrys AJ. Aust. Road Res. 1988; 18(3): 173-181.

Affiliation

University of Auckland, Auckland, NZ

Copyright

(Copyright © 1988, Australian Road Research Board ARRB)

DOI

unavailable

PMID

unavailable

Abstract

The Type 400 motorway sign is a changeable message sign that can display a red cross or a white or green arrow. This paper reports an investigation of the visibility of Type 400 motorway signs on the Auckland Harbour Bridge. When operated at the maximum voltage of 24V and measured on axis, the signals had an intensity of 412 cd for a red cross and 665 cd for a green arrow. When measured 2.5 degrees off axis and with the signals operating at 22 V, the mean intensities were 163 cd for the red cross and 389 cd for the green arrow. Signal intensities were generally found to be below the requirements of national and international standards. A decrease in signal intensities due to damage to reflectors and fiber optics caused by heating from the light bulbs was observed for signals in service. Sunlight falling on the signs produced a veiling luminance. Aging of the screen reduced signal contrast.

Language: en