Purpose – The purpose of this paper is to investigate the impact of risk on the project delivery selection process of three primary methods in use in the USA, including design-bid-build (DBB); design-build (DB); and construction manager/general contractor (CMGC). Design/methodology/approach – The review of empirical studies, national survey questionnaire, multivariate analysis, and cross-validating discussion are adopted for this research. The risk factors were identified through an exhaustive literature review and empirical studies that included more than $10 billion of transportation projects. Experts with an average of 25 years of professional experience related to risk and project delivery methods in the transportation industry were invited to participate in the survey. Findings – There were six critical risk factors for DBB, seven for DB, and six for CMGC. These critical risk factors are ranked differently from each delivery method. The most critical risk factor for DBB is construction risk, for DB is scope risk, and for CMGC is constructability and documentation risk. Research limitations/implications – Knowledge of the risk factors will allow researchers to better understand the impact of risk on DBB, DB, and CMGC projects. The chief limitation of this research is that the primary data were mostly opinions from experts although several empirical data were collected for cross-validation. The future research may take into account the role of participant's risk aversion in project delivery decision frameworks. Practical implications – Transportation agencies and other practitioners can use these risk factors to make more effective and defensible decisions on which delivery method is the most suitable for their projects. The result from this study provides a foundation for decision makers to use a risk-based approach in the project delivery decision. Originality/value – This research is the first attempt to examine the impact of risk on the project delivery selection process.