Impact of Free Flow Speed Estimation Method on Project Prioritization
Publication: International Conference on Transportation and Development 2024
ABSTRACT
Transportation project prioritization relies heavily on assessments of performance and outcome; however, inconsistencies in analytical techniques of performance measures can significantly skew the results. This study conducts a comprehensive examination of free-flow speed (FFS) estimation methods and the impact of delay threshold selection, demonstrating their pivotal roles in result interpretation and project prioritization. A comparative analysis of several FFS estimation methodologies reveals that methods based on the 85th percentile of observed speeds yield highly correlated FFS estimates, while the 95th percentile methods or simple arithmetic operations of posted speed limits produce divergent results. Moreover, the study underscores the substantial influence of congestion threshold selection on the calculated delay, exhibiting significant variation at statewide, district, and corridor levels. These thresholds not only affect the magnitude of calculated delays but also alter the perceived severity of congestion. The research results underscore the vital need for transportation agencies to adopt standardized methodologies for FFS estimation and congestion delay threshold selection in order to enable consistent, unbiased project evaluation and data-driven prioritization.
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International Conference on Transportation and Development 2024
Pages: 750 - 761
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Published online: Jun 13, 2024
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