Maintenance of Traffic for Innovative Geometric Design Work Zones

Abstract

In an effort to improve the safety and capacity of existing roads, many transportation practitioners are implementing innovative designs at intersections and interchanges. The development of construction phasing plans for these projects is a critical component for maintaining safety and mobility on the facility during construction. The goal of this study was to address the gaps in existing knowledge by presenting the state of the practice and providing guidance for transportation practitioners in developing construction phasing and maintenance of traffic (MOT) plans for projects with innovative geometric designs. Several types of innovative geometric designs were studied, including the round about, single-point urban interchange, diverging diamond interchange, restricted-crossing left turn, median U-turn, and displaced left turn. Examples of MOT phasing diagrams showing phasing sequencing and construction work areas were developed on the basis of a review of the literature, a survey of practitioners, interviews with industry experts, and a review of actual project plans. The examples of MOT phasing diagrams are intended to serve as a starting point for transportation practitioners, but project-specific factors such as driver experience, availability of detours, traffic counts, adjacent land use, elevation differences, barrier offsets, number of lanes, and anticipated impacts of a possible closure should be considered when deciding on the best MOT methods for a given project.