@article{ref1,
title="Improving Steep Bends As Hairpin Curves on Mountainous Roads",
journal="Journal of transportation engineering",
year="1990",
author="Roy, B. K.",
volume="116",
number="5",
pages="667-682",
abstract="[Abstract unavailable]  <p>Language: en</p>",
language="en",
issn="0733-947X",
doi="",
url="http://dx.doi.org/"
}