Like other state departments of transportation, the Oregon Department of Transportation (ODOT) has emphasized preservation of existing highways and bridges. Thus, ODOT has done construction and maintenance work at night in order to minimize the disruption of daytime traffic. However, nighttime operations produce a new set of concerns such as safety, public relations, productivity, and quality. Decision-making for using nighttime operations in Oregon has been subjective and has relied on judgment without the benefit of analytical data and evaluation criteria. Therefore, a decision model that facilitates the determination of when to use nighttime road construction and maintenance work was developed. From the literature review, 19 factors affecting decision-making were identified and used to create a survey. The investigators surveyed ODOT personnel, ODOT’s contractors, and the representative personnel from other departments of transportation. After analyses of various perspectives, the overall result was fairly consistent with the results from the individual respondent groups. The results provided the ability to eliminate unimportant factors, determine weights of important factors, and build a decision model to improve the effectiveness of decision-making. The decision model was tested by applying it to actual ODOT projects and comparing its recommendations on when to conduct the projects with actual decision makers’ decisions. The overall testing results were consistent with current decision makers’ subjective decisions because of the impact of congestion within the decision model. The decision model in this study provides a practical and useful tool to help decision makers in real work environments analyze when to use nighttime work. The model will be useful for making decisions consistently and provides a means to explain the decision to the stakeholders.