Citation

Slocum RW, Prabudy DR. Transp. Res. Rec. 1979; 737: 86-91.

Copyright

(Copyright © 1979, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

A key issue in the field of illumination is energy conservation. At the same time, the application of economic resources should be optimized. For instance, to save energy, roadway illumination lamps can be replaced by more efficient lamps that provide the same light for less wattage. However, such energy savings may be offset by other cost elements. For these reasons, detailed cost calculations are needed to ensure lighting investment optimization. The cost-effectiveness of lighting systems can be established by the discounted total cost or annual equivalent cost models described in this report. These economic models allow various cost items, such as capital outlay, maintenance, and operational and energy costs, to be compared realistically by taking into account discount rates and inflation rates. Consideration of inflation is particularly important here because some costs, notably energy, may inflate at higher rates than other costs. The methods given in this paper provide for the inclusion of projected dollar cost inflation in the analysis. A computer program for the models has been developed, copies of which may be obtained from the author, and can be used independently or in conjunction with the overall illumination program. This computer program allows a comparison of different strategies by varying the input values of costs, as well as inflation and discount rates. The most effective design solution can then be identified and considered in the overall evaluation of the alternatives. The program should be a useful tool in selecting designs of light sources and other features of roadway lighting systems.