Overview
The goal of the SHRP 2 L33 Validation of Urban Freeways project is to assess and enhance the predictive travel time reliability models developed in the SHRP 2 L03 project, Analytical Procedures for Determining the Impacts of Reliability Mitigation Strategies. SHRP 2 L03, which concluded in 2010, developed two categories of reliability models to be used for the estimation or prediction of travel time reliability within planning, programming, and systems management contexts: data-rich and data-poor models.
The L33 project was tasked with (1) validating the data-rich and data-poor equations with new data sets; (2) assessing the validation outcomes to recommend potential enhancements; (3) exploring enhancements and developing a final set of predictive equations; (4) validating the enhanced models; and (5) developing a clear set of application guidelines for practitioners to use with the project outputs.
The work outputs of this project include a set of recalibrated data-poor models, a set of enhanced data-rich models, and revised application guidelines for using the models.