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Title: Seemingly Unrelated Regression Model of Car Speeds and Speed Deviations in Freeway Work Zones
Accession Number: 01049273
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: Current work zone design and traffic control guidance is based heavily on desirable speed-related outcomes, but knowledge concerning actual speed-related outcomes of design and traffic control decisions is limited. The objective of this research is to investigate relationships between speed behavior, roadway and roadside geometrics, and traffic control in work zones. The objective is accomplished through specification and estimation of a seemingly unrelated regression (SUR) model. The dependent variables modeled were 85th-percentile passenger car speed and standard deviation of passenger car speed. Work zone design and traffic control features were investigated as explanatory variables. Speed and infrastructure data used for estimation were collected in Pennsylvania and Texas work zones. The SUR model accounted for contemporaneous correlations of the disturbance terms in the two speed equations. In the equation for 85th-percentile speed, regression parameters were statistically significant for variables representing work zone configuration, type of roadway infrastructure, work zone location, distance traveled from the beginning of the work zone, posted speed limit, vertical alignment, and total paved cross-section width. In the equation for standard deviation of speed, parameters were statistically significant for variables representing distance traveled from the beginning of the work zone, total paved cross-section width, and reduction in posted speed and roadside conditions. Several recommendations for future work are provided, including expansion of the system of equations to include 85th-percentile truck speeds and standard deviation of truck speeds and consideration of possible contemporaneous relationships between speed measures.
Monograph Title: Monograph Accession #: 01088318
Language: English
Authors: Porter, Richard JMahoney, Kevin MMason Jr, John MPagination: pp 44-51
Publication Date: 2007
ISBN: 9780309104500
Media Type: Print
Features: Figures
(2)
; References
(17)
; Tables
(9)
TRT Terms: Subject Areas: Data and Information Technology; Design; Highways; Operations and Traffic Management; I20: Design and Planning of Transport Infrastructure; I73: Traffic Control
Files: TRIS, TRB, ATRI
Created Date: Feb 8 2007 6:54PM
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