Part I will provide comprehensive information on U-turn-based intersections, covering key issues related to planning, implementation, operation, and maintenance; and Part II will provide an expanded resource on A.I.I.s, focusing on the efficacy of underutilized, emerging, or new concepts, as well as their variations. To achieve the research objective, the research team shall, at a minimum, consider the following key elements: Identification and evaluation of existing and emerging alternative design concepts and treatments in the United States and internationally; Review of research and practices that complement the objectives and address gaps in previous guides (see Special Note A); Development of criteria for applying appropriate treatments and design features based on context (e.g., traffic data, land use and access, expected users, roadway data, speed, flexibility); Consideration of all modes of transportation and users of all ages and abilities; Preparation of standardized definitions of terms; and Harmonization with applicable standards and guidelines.
