@article{ref1,
title="Development of left-turn lane warrants for unsignalized intersections",
journal="Transportation research record",
year="2012",
author="Fitzpatrick, Kay and Brewer, Marcus A. and Eisele, William L. and Zhang, Yunlong and Gluck, Jerome S. and Levinson, Herbert S. and Iragavarapu, Vichika",
volume="2301",
number="",
pages="55-65",
abstract="Left-turn movements at intersections, including driveways--especially movements that are made from lanes that are shared with through traffic--cause delays and adversely affect safety. Although some left-turn warrants have been updated, many agencies still use research performed by M. D. Harmelink in the mid-1960s. Most states use procedures that are based on Harmelink's work, but several limitations have been identified. Economic analysis can provide a useful method for combining traffic operations and safety benefits of left-turn lanes to identify situations in which left-turn lanes either are or are not justified economically. This project used a benefit-cost approach to determine when a left-turn lane would be justified. The steps included simulation to determine delay savings from installing a left-turn lane, crash costs and crash reduction savings determined from safety performance functions and crash modification factors available in the Highway Safety Manual, and construction costs. Left-turn lane warrants were developed for rural two-lane highways, rural four-lane highways, and urban and suburban roadways. In addition, warrants for bypass lanes were developed for rural two-lane highways.<p />",
language="en",
issn="0361-1981",
doi="",
url="http://dx.doi.org/"
}