Traffic Stream Model Evaluation under Inclement Weather Conditions using a Fused Database
Estimating the travel time reliability of freeway facilities is a challenge in front of transportation researchers nowadays. Travel times are estimated based on freeway facilities key performance measure like, free-flow speed (FFS) and capacity. The performance measures are estimated under different prevailing recurring or non-recurring congestion sources. The accurate estimation of freeway facilities performance measures leads to better travel time estimation. This paper aims to compare models and methods in estimating key performance measures under inclement weather conditions and come up with the best approach. To this end, traffic, weather, and incident databases were fused using a heuristic algorithm. Northwestern, Van Aerde, Modified Greenshields, and HCM traffic stream models were evaluated against the field data under normal, light rain, medium rain, heavy rain, and snow weather in both undersaturated and oversaturated regimes. Free-flow speed and capacity of the freeway facility were estimated using model parameters and empirical threshold methods. The research findings indicate that the dual-regime Modified Greenshields model provides the best estimate among all, however, all the models fail to provide reasonable capacity estimation. Therefore, it is suggested to use an empirical thresholds approach, with either 1% or 5% threshold. The threshold heavily relies on total number of observations in all the scenarios. Using the recommended approaches for FFS and capacity estimation, there are 6%, 10%, 12%, and 30% drop in the estimated FFS and 4%, 5%, 6%, 26% drop in the estimated capacity as a result of the light rain, medium rain, heavy rain, and snow weather conditions respectively.
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Supplemental Notes:
- This paper was sponsored by TRB committee AHB40 Highway Capacity and Quality of Service. Alternate title: Traffic Stream Model Evaluation under Inclement Weather Condition through a Fused Database Approach
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Corporate Authors:
500 Fifth Street, NW
Washington, DC United States 20001 -
Authors:
- Sajjadi, Soheil
- Schroeder, Bastian
- Rouphail, Nagui
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Conference:
- Transportation Research Board 93rd Annual Meeting
- Location: Washington DC
- Date: 2014-1-12 to 2014-1-16
- Date: 2014
Language
- English
Media Info
- Media Type: Digital/other
- Features: Figures; References; Tables;
- Pagination: 23p
- Monograph Title: TRB 93rd Annual Meeting Compendium of Papers
Subject/Index Terms
- TRT Terms: Databases; Estimating; Freeways; Reliability; Traffic congestion; Travel time; Weather conditions
- Subject Areas: Highways; Planning and Forecasting; I72: Traffic and Transport Planning;
Filing Info
- Accession Number: 01515572
- Record Type: Publication
- Report/Paper Numbers: 14-5630
- Files: TRIS, TRB, ATRI
- Created Date: Feb 24 2014 8:43AM