Citation

Jung W, Kazakov A, Titishov AI. Transp. Res. Rec. 1984; 996: 24-37.

Copyright

(Copyright © 1984, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

A photometer for measuring surface reflectance matrices of dry pavements was developed at the University of Toronto and has been used to measure the light reflectance properties of many pavements in Ontario. The laboratory measurements were carried out on 6-in. diameter samples, and statistical deviations were carefully studied to determine the feasibility of classifying the pavements in accordance with Committee International de l'Eclairage (CIE) and (more recent) Illumination Engineering Society (IES) practice and to establish a reliable sampling procedure. The measured pavement types were classified on the basis of their reflectance parameters (Q0, S1, S2) established as average values from reflectance matrices of at least three samples. These parameters were found to be dependent on aggregate polishing and stone brightness, and on accumulated traffic load. The influence on the light reflectance of the viewing angle a being different from the standard 1 degree was also studied, and it was found that all parameters tend to decrease with increasing angle a. The findings indicate that reflection properties can be measured with fair accuracy and confidence, but that significant fluctuations of the reflectance properties can occur on a given pavement. The IES or CIE proposal for four specularity classifications under dry conditions can be recommended; however, the brightness parameter, Q0, was found to be of greater significance in lighting than originally anticipated and more accurate values should be established as discussed in this paper.

Language: en

Keywords

ROADS AND STREETS; VISIBILITY - Evaluation; LIGHT - Reflection