HIGHWAYS LIGHTING

Evening Post, Volume CXXIII, Issue 56, 8 March 1937, Page 11

HIGHWAYS LIGHTING

Recently art article was published in "The Post" referring to modern.highway lighting and the use of sodium or mercury vapour lamps overseas and the tests and inquiries being made in their installation on New Zealand main highways. One striking test which has been made locally is that in Mount Victoria tunnel, with mercury lamps at one end and sodium lamps at the other. A correspondent disagrees with some of the statements made, and says that extensive tests carried out some time ago in the United States went, to show that the same visibility of objects on highways is experienced with either incandescent, sodium vapour, or mercury vapour lamps with the premises that the illumination from each is

equal. Modern research, he states, has shown that the main requirement is that each portion of the roadway should be directly illuminated from at least two units. The same results .can be obtained with incandescent lamps, in many cases just as efficiently as with vapour lamps: it is all a question of economics, and the selection of one system or another depends upon the initial cost, the cost of maintenance, and the cost of power. When anything new is introduced, the correspondent concludes, many consider that it is a cure for all things, not realising -its limitations alongside its undoubted advanta?'"