@article{ref1,
title="Traffic signals and accidents in Michigan",
journal="Traffic safety research review",
year="1960",
author="Solomon, David",
volume="4",
number="2",
pages="18-22",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0564-0741",
doi="",
url="http://dx.doi.org/"
}