Development of a decision-support tool for TxDOT delivery methods selection
Alternative delivery methods for transportation infrastructure projects, besides the traditional Design-Bid-Build (DBB) approach, have been implemented by private and public sectors since the last decades. The Texas Department of Transportation (TxDOT) is not the exception, and the fact that TxDOT has available alternatives for delivering its projects lead to the need of a formal decision process. This work presents the existent approaches made by different owner entities to formalize the delivery method decision. This research provides with decision procedures, criteria and principles to develop a quantitative decision-support tool; thus serving any entity seeking for a formalized and documentable Delivery Method decision procedure. A complete decision process was developed specifically for TxDOT, based on the literature review findings, but also on the agency's needs, experience and legal authority. This work intends to help the agency's staff make an informed choice between their available delivery methods: Design-Bid-Build and Design-Build. The decision method was formalized in the way of a Multiple Criteria Decision Making (MCDM) process, and organized as a MS Excel decision-support tool. The process incorporates knowledge --in the shape of performance scores-- from TxDOT experts as well as from other organizations that work closely with the agency. This input allows for the creation of a tool fully customized for TxDOT goals and projects' characteristics. The decision-support tool developed incorporates quantitative measures, but is transparent and flexible. It constitutes a rigorous, repeatable and documentable decision process, evaluating characteristics and goals of each project to determine each delivery method’s suitability degree. Overall, the present works provides with guidelines for the development of a decision-support tool regarding the delivery methods decisions for any entity needing to formalize the process. It also specifically contributes to TxDOT, producing a formalized decision process that may be taken as an example for any other entity willing to modify and quantify their current Delivery Method selection procedure.