Modeling the Causal Relationships between Winter Highway Maintenance, Adverse Weather and Mobility.

Author(s)
Qiu, L. & Nixon, W.A.
Year
Abstract

This paper explored the direct and indirect causal effects of adverse weather and winter maintenance actions on mobility as measured by traveling speed and traffic volume. Using Structural Equation Modeling (SEM) with the particular Categorical Variable Methodology (CVM), the paper analyzed the weather, maintenance and traffic data from 2001 to 2004 in the State of Iowa. Separate structure models were fit simultaneously to subgroups, which are disaggregated by road classification, Annual Average Daily Traffic (AADT) and speed limit. The analysis results suggest that despite winter maintenance operations that might slow down traffic during the hour when they are performed, winter maintenance operations have significant positive effects on improving speed, and the positive effects have been fully mediated through road surface conditions. Compared to the effects of plowing and applying chemicals, sanding is the least influential operational method to improve speed. Also the analyses suggest that the influences are different across road classifications, speed limits and different levels of AADT.

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Publication

Library number
C 43921 (In: C 43862 CD-ROM) /62 / ITRD E838803
Source

In: Compendium of papers CD-ROM 87th Annual Meeting of the Transportation Research Board TRB, Washington, D.C., January 13-17, 2008, 16 p.

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This publication is one of our other publications, and part of our extensive collection of road safety literature, that also includes the SWOV publications.