@article{ref1,
title="Background and objectives of the U.S. standard for colors of signal lights",
journal="Highway Research Board bulletin",
year="1959",
author="Breckenridge, F. C.",
volume="226",
number="",
pages="7-13",
abstract="The U.S. Standard for colors of signal lights embodies an attempt to eliminate some of inconsistencies between different specifications for signal-light colors now used in the United States on the basis of the recommendations of the International Commission on Illumination. Differences in service conditions justify some of the differences among these specifications, but not all of them. The report also explains the different purposes served by the several parts of the standards and the relationship of basic definitions, limit standards, and procurement specifications.<p />",
language="",
issn="0073-2206",
doi="",
url="http://dx.doi.org/"
}