Description
| Abstract: | Safety prediction models have been developed for urban freeway segments in Texas and elsewhere to apply to cross sections up to 10 lanes wide. These models are documented resources such as TxDOT's Roadway Safety Design Workbook and the Highway Safety Manual and applied in several spreadsheet-based analysis tools. These tools are acknowledged in the Project Development Process Manual and have been used by various district personnel, particularly in the evaluation of project alternatives or analysis of design exceptions. However, additional research is needed to address knowledge gaps as well as to develop updated local calibration factors for the models. Specifically, safety prediction models do not exist for 12-lane freeway segments or freeway segments with managed lanes (e.g., high-occupancy-vehicle or high-occupancy-toll lanes). The research team derived local calibration factors for models for urban freeway segments with 4-10 lanes, assessed the applicability of the 10-lane urban freeway model to freeway segments with 11 or more lanes, and developed new safety prediction models for segments with managed lanes. The research team also developed an analysis tool to help practitioners implement the new models to facilitate analysis of complex urban freeway configurations, such as cases where an urban freeway widening project requires challenging tradeoffs between narrowing lanes or inside or outside shoulders. |
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| Item Description: | Includes the "Highway Safety Manual Calculations for Texas" (Excel file), developed by Michael P. Pratt and Srinivas R. Geedipally. This software may be used to estimate crash frequency on freeways, ramps, and frontage roads as a function of geometric, access, and traffic control data following the Highway Safety Manual methodology. |
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| Physical Description: | 1 online resource (ix, 62 pages) : illustrations (some colord) + 1 program file. |
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| Bibliography: | Includes bibliographical references (pages 59-62). |
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| Access: | Open access content |
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