Details:

Creators:
Young, Rhonda ; Sabawat, Vijay ; Saha, Promothes ; Sui, Yanfei
Young, Rhonda ; Sabawat, Vijay ; Saha, Promothes ; Sui, Yanfei Less -
Corporate Creators:
University of Wyoming. Dept. of Civil and Architectural Engineering
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Compliance Evaluation Highway Corridors Highway Safety Rural Highways Variable Speed Limits
Publication/ Report Number:
FHWA-WY-13/03F
Resource Type:
Tech Report
Geographical Coverage:
Wyoming
Corporate Publisher:
Wyoming. Dept. of Transportation
Abstract:
The Wyoming Department of Transportation (WYDOT) installed its first variable speed limit (VSL) corridor along

Interstate 80 in the Elk Mountain Corridor in the Spring of 2009 in an effort to improve safety and reduce road closures,

particularly during winter storm events. Since that time, four additional variable speed limit corridors have been

implemented; three additional corridors along segments of Interstate 80 and one on WY 28, a rural two lane highway

through the area of South Pass. There were three main objectives to this research effort: develop control strategy for the

operation of VSL corridors, analyze the safety effects of the VSL system, and determine the impacts of the VSL on driver

speed behavior. For the development of a control strategy, both weather and speed variables were considered. Initially a

simple linear regression approach was considered but the complexity of the weather and speed behavior led to a regression

tree based control strategy with a self-learning feedback loop using machine learning. For the safety task, descriptive

baseline safety was analyzed for all five corridors. Since the Elk Mountain Corridor is the only VSL system in operation

for more than two winter seasons, it was used for an Empirical Bayes (EB) before and after analysis, which indicated some

statistically significant changes in crash frequency for just a few of the corridor segments. A weather-based safety analysis

was performed on the four interstate VSL corridors and results from this analysis indicate a statistically significant

reduction in crashes after the VSLs were implemented. Analyses of speed variables indicate a reduction in speed variation

with the implementation of the VSL system. Modeling of the difference between observed and posted speeds show a

reduction in speed compliance related to large reductions in posted speed limits.


Format:
PDF
Funding:
RS04(210)
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:4c03852a20d90d6eb1780d928caa9727491634ab78a53c5bd0b88d38c796097e
Download URL:
https://rosap.ntl.bts.gov/view/dot/29333/dot_29333_DS1.pdf
File Type:

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