This paper reviews the simplified procedure proposed by Ghosn and Sivakumar to model the maximum expected traffic load effect on highway bridges and illustrates the methodology using a set of Weigh-In-Motion (WIM) data collected on one site in the U.S. The paper compares different approaches for implementing the procedure and explores the effects of limitations in the sitespecific data on the projected maximum live load effect for different bridge service lives. A sensitivity analysis is carried out on the most representative variables involved in the WIM data collection and calculation of the maximum load effect. The procedure is implemented on a set of WIM data collected in Slovenia to study the maximum load effect on existing Slovenian highway bridges and how it compares with the values obtained from the Eurocode of actions.