Front End Planning (FEP) is a critical process for uncovering project unknowns, while developing adequate scope definition following a structured approach for the project execution process. FEP for infrastructure projects assists in identifying and mitigating issues such as right-of-way concerns, utility adjustments, environmental hazards, logistic problems, and permitting requirements. This thesis describes a novel and effective risk management tool that has been developed by the Construction Industry Institute (CII) called the Project Definition Rating Index (PDRI) for infrastructure projects. Input from industry professionals from over 30 companies was used in the tool development which is specifically focused on FEP. Data from actual projects are given showing the efficacy of the tool. Critical success factors for FEP of infrastructure projects are shared. The research shows that a finite and specific list of issues related to scope definition of infrastructure projects can be developed. The thesis also concludes that the PDRI score indicates the current level of scope definition and corresponds to project performance. Infrastructure projects with low PDRI scores outperform projects with high PDRI scores.