Many methods for highway cost allocation procedures have been adopted previously by all levels of government; local, state, and federal. However, they rarely address the issue of long span bridge allocation properly, simply treating these unique structures as the typical short span bridge. This methodology can lead to grossly inaccurate results. Consequently, this thesis seeks to identify a method to be supplemented in conjunction with the commonly accepted approaches in order to address this problem and provide a thorough highway cost allocation analysis. In addition to discussion regarding the recommended procedures, alternative approaches, along with their pros and cons will be presented. Finally, results of the sensibility studies will be examined as supplemental information to ensure the accuracy of the recommended approach.