Measuring User Perceptions of Popular Transportation Project Delivery Methods Using Least Significant Difference Intervals and Multiple Range Tests

Abstract

One of the most critical decisions made by transportation project stakeholders is the choice of a project delivery method for their project. Delivery methods have been shown to significantly impact project cost and schedule. As the use of alternative project delivery methods increases, the perceptions of the advantages and disadvantages to using a particular method have matured. This paper reports on a national study of over 8 transportation owners and designers to measure their perceptions of the three most widely used delivery methods: design bid build (DBB), construction manager at risk (CMAR), and design build (DB). The study develops a list of factors that influence the selection of a delivery method, and then tests the most significant factors that lead to the selection of each individual method. Analyses using Fisher’s least significant difference intervals and multiple range tests allow for the identification of specific correlations between the delivery method and motivating factors or project goals. The analyses show that delivery method selection is motivated primarily by project urgency, cost, and risk allocation. For the three main delivery methods of DBB, CMAR, and DB, motivation for their selection is primarily based on cost, risk allocation, and project urgency, respectively. User perceptions align with findings from literature in terms of schedule performance, but do not align in terms of cost performance. This research contributes to the body of knowledge by reporting on the most current motivating factors for the selection and use of the most popular delivery methods.