This report deals with the unique and first time application in Canada of a driver simulator to assess a complex at-grade rail crossing design. Based on recommendations from a road safety oriented peer review of a proposed upgrade design of a railway grade crossing in the City of Ottawa, the purpose of this simulation was to optimize the positive guidance offered to drivers using the crossing and associated roadway elements, by designing a more understandable, visible and driver-oriented approach environment. The first section of this paper provides an overview of the existing grade crossing environment and the challenges created by planned road network and development changes in the vicinity of the crossing. The technical complexity and features associated with the proposed design solution that lead to the decision to use a driver-simulator approach to the evaluation of positive guidance and warning systems at this grade crossing are also discussed. In the second section we discuss the data and information requirements necessary to construct the computer model for insertion into the driver simulator – and the particular challenges encountered in meeting these needs. The penultimate section of the paper details the specifics of the simulator study design, with a specific focus on the human factors methodology and considerations used to evaluate the performance of drivers within the proposed crossing environment. Observational driver behaviour and eye movement measures collected during participants’ drives are examined and key findings of the study are summarized. The report concludes with a discussion of the advantages, limitations, and challenges associated with using a driver simulator approach to evaluating real-world application scenarios.