Peak spreading is becoming common on urban roadways as existing facilities reach capacity and traffic volumes continue to grow. Being able to accurately model peak spreading behavior is necessary to accurately assess the travel time saving benefits of capital improvement projects, in addition to other reasons. Several types of peak spreading models have been developed in recent years, each with varying levels of success and limitations. This report used historical data and trends to develop a peak spreading model for the Seattle metropolitan area. A two-part model was used in an attempt to develop a stand-alone peak-spreading model. Although this model did not produce the intended results, it serves as an important step in the process. The use of a logit model to predict the peak spreading phenomenon is an innovative approach that deserves additional study.