@article{ref1,
title="Concrete barriers at transition zones adjacent to two-way traffic operation on normally divided highways",
journal="Transportation research record",
year="1981",
author="Pang, Leslie M. G. and Yu, Jason C.",
volume="833",
number="",
pages="10-13",
abstract="One technique to control traffic around construction zones on four-lane divided highways is to close one of the roadways for construction work and provide two-way, two-lane operations on the opposite roadway. Because of the high frequency of head-on collisions under this type of traffic control, the Federal Highway Administration issued an emergency rule that, among other things, requires that concrete barriers be placed at the transition zones where four-lane operations change to two-lane and vice versa. The objective of this study was to verify whether barriers are justified at transition zones on the basis of accident experience. Data from 14 rural Interstate work sites showed that no head-on accidents occurred at the transitions but several occurred on the two-way, two-lane segments. This indicates that, at least on lesser-traveled highways, the probability of a head-on collision is low because of the minimal volume of oncoming traffic. Therefore, the barrier requirement is questionable on low-volume roadways. By using intuitive reasoning, the effects of project duration and approach speed on accident behavior in transition zones are also discussed.<p />",
language="en",
issn="0361-1981",
doi="",
url="http://dx.doi.org/"
}