Determining Level of Service on Freeways and Multilane Highways with Higher Speeds
The Highway Capacity Manual provides a means for evaluating level of service on freeways, highways, and urban streets. Presently, the Highway Capacity Manual methodology is not able to evaluate level of service on freeways with free-flow speeds greater than 75 mph or multilane highways with free-flow speeds greater than 60 mph, and many states now have facilities with posted speed limits that exceed these free-flow speeds. Recent research, conducted by the Texas A&M Transportation Institute (TTI), developed speed prediction equations for uninterrupted flow facilities with higher posted speed limits. From these equations, this paper develops procedures for calculating free-flow speed on facilities with higher posted speed limits and develops methods for estimating level of service on freeways with free-flow speeds up to 85 mph and multilane highways with free-flow speeds up to 80 mph. For freeways, the recommendations call for utilizing the TTI speed prediction equations to calculate free-flow speed and using the calculated free-flow speeds to determine level of service from speed–flow curves developed within this paper. For multilane highways, recommendations call for utilizing the TTI speed prediction equations to calculate base free-flow speed, which is part of the equation for calculating free-flow speed, and then using the calculated free-flow speed to determine level of service from speed–flow curves developed within this paper. To aid practitioners, step-by-step procedures are provided for applying the TTI speed prediction equations within the Highway Capacity Manual methodology.
- Record URL:
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Availability:
- Find a library where document is available. Order URL: http://www.trb.org/Main/Blurbs/172274.aspx
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Authors:
- Robertson, James
- Fitzpatrick, Kay
- Park, Eun S
- Iragavarapu, Vichika
- Publication Date: 2014
Language
- English
Media Info
- Media Type: Print
- Features: Figures; References; Tables;
- Pagination: pp 85–93
- Monograph Title: Highway Capacity and Quality of Service 2014
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Serial:
- Transportation Research Record: Journal of the Transportation Research Board
- Issue Number: 2461
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Calculation; Free flow speeds; Freeways; Level of service; Methodology
- Uncontrolled Terms: Speed estimation
- Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting; I72: Traffic and Transport Planning;
Filing Info
- Accession Number: 01518267
- Record Type: Publication
- ISBN: 9780309295550
- Report/Paper Numbers: 14-0838
- Files: PRP, TRIS, TRB, ATRI
- Created Date: Mar 14 2014 9:25AM