@article{ref1,
title="Four-lane to five-lane urban roadway conversions for safety",
journal="Journal of transportation safety and security",
year="2013",
author="Sun, Xiaoduan and Das, Subasish and Fruge, Nicholas and Bertinot, Ronald L. and Magri, Daniel",
volume="5",
number="2",
pages="106-117",
abstract="Undivided roadways have consistently exhibited low safety performance, particularly in urban or suburban areas where roadside development is relatively intense. Changing a four-lane undivided road to a divided roadway by either building a boulevard cross-section or installing a physical barrier is a desirable option to improve safety performance of an undivided roadway, but it requires significant resources. This article introduces a crash countermeasure successfully implemented on two different segments of undivided roadways in Louisiana. This crash countermeasure is to change an undivided four-lane roadway to a five-lane roadway with a center lane for left turns by restriping pavement markings without increasing pavement width. Although the five-lane roadway is no longer an acceptable roadway type in Louisiana, the impressive crash reductions on both roadway segments demonstrate it is a feasible solution under constrained conditions. Based on the statistical analysis with 6 years of crash data (3 years before and 3 years after excluding the implementation year), the crash modification factors for both roadways are estimated to be less than 0.5 with a standard deviation less than 0.07. Although it is not surprising to see the biggest crash reduction comes from the rear-end collisions, the other types of collision are also reduced.<p />",
language="en",
issn="1943-9962",
doi="10.1080/19439962.2012.711439",
url="http://dx.doi.org/10.1080/19439962.2012.711439"
}