As an increasing number of highway projects are undertaken in highly congested metropolitan settings, many of such projects require that adjacent utilities be adjusted to accommodate new or expanded highway facilities. The adjustment of utilities prior to highway construction is a particularly complex and challenging operation. Because of its complexity, managing utility adjustment is fraught with risk and uncertainty. One major strategic approach that has emerged over the past 15 years is to combine utility adjustment work with the highway contractor’s scope of work. Since it allows for better coordination between involved parties, this approach theoretically eliminates or reduces adjustment-related complications and risks and is referred to in this research as the Combined Transportation and Utility Construction (CTUC) approach. While the CTUC approach offers many benefits, it does have its own set of challenges and disadvantages. Many of these difficulties involve disagreements between the state Department of Transportation (DOT) and utility owners over the appropriateness of CTUC for particular projects. Given the complications of the issues involved, there is a significant need for a decision support model to provide guidance to state DOT and utility decision makers as to when the CTUC approach should be applied. This research aims to design a decision support model to represent the CTUC decision knowledge of experts from both the state DOT and utility owners, to develop a decision support tool to assist both parties’ decision makers in identifying significant issues, and to verify and validate the proposed decision support model and tool. Based on the model verification and validation results, this CTUC tool can: (1) help both parties make a CTUC decision in a more efficient and effective way; (2) determine the conflicting issues between parties; (3) reduce the number of the issues that need to be considered simultaneously; and (4) provide guidelines for determining the applicability of the CTUC approach, especially for less experienced project stakeholders or managers.