Book Description

Many Departments of Transportation (DOTs) have done construction and maintenance work at night in order to minimize the disruption of daytime traffic, but nighttime operations produce a new set of concerns such as safety, public relations, productivity, and work quality. In addition, decision-making for using nighttime operations has been subjective and has relied on judgment without benefit of analytical data and evaluation criteria. Therefore, a decision model that truly facilitates the determination of when to use nighttime road construction and maintenance work has been developed. A comprehensive list of well-defined and articulated factors was developed through extensive literature review, but prior research did not delineate the relative importance of the various factors. Thus, this research study surveyed Oregon DOT personnel, its contractors, and the representative personnel from other states' DOTs. After analyses of various perspectives, the overall result was fairly consistent with the results from the individual respondent groups. The results allowed the elimination of unimportant factors and the determination of the weights of important factors. Subsequently, the most important factors were analyzed for their impact on the choice between daytime versus nighttime work in selected states. This permitted the decision model to be generalized. Whenever possible, factors were quantified with tangible score values for daytime versus nighttime. Using this information, a decision model was developed. The decision model was tested by applying it to actual projects and comparing the model's recommendations on when to conduct the projects with actual decision makers' decisions. The overall testing results were consistent with current decision makers' subjective judgments because of the impact of congestion, safety, and productivity in the decision model. In addition, sensitivity analysis showed the deviations of decision-making in the decision model. Finally, the decision model was evaluated by experts in this field to examine practicality, usefulness, and user-friendliness of the model. The decision model in this study has successfully provided a practical and useful tool to help decision makers in real work environments analyze when to use nighttime work. Also, the model will be useful in making decisions consistently and in providing a means to explain the decision to stakeholders.