This second Strategic Highway Research Program (SHRP 2) L33 report, titled “Validation of Urban Freeway Models,” documents and presents the results of a project to investigate, validate, and enhance the travel time reliability models developed in the SHRP 2 L03 project, titled “Analytic Procedures for Determining the Impacts of Reliability Mitigation Strategies.” L03 developed several travel time reliability models, segregated into two sets, called data rich models and data poor models. The data poor models take in inputs on the mean travel time and give travel time percentiles as outputs. The data rich models also give as output the travel time percentiles, taking in additional variables on incidents, weather, demand, and capacity. This report used new data sets and statistical performance measures to rigorously validate these models. As part of this validation, this work examined the structure, inputs, and outputs of all of the L33 models and came to conclusions on the applicability and validity of all L03 models. This report then proposes new application guidelines and enhancements to the L03 models, in order to make them more useful and relevant to the transportation community. Ultimately the goal of this effort is to enhance the ability of transportation practitioners to accurately predict the reliability impacts of transportation investments. (Author/publisher)
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