Updated Guidance on Reduced Left-Turn Conflict Intersections

Alternative intersection and interchange (A.I.I.) designs initially emerged as a way to improve safety and operations while reducing project costs and impacts, with the potential to enhance facilities for pedestrians and bicyclists. Early consideration and implementation by agencies were supported by the Federal Highway Administration (FHWA) Alternative Intersections/Interchanges Informational Report and a series of informational guides published since 2014. More recently, the North Carolina Department of Transportation (NCDOT) released an annotated outline for an updated informational report, and FHWA published a new guide focused on pedestrian and bicyclist safety at alternative intersections. Additionally, recent NCHRP reports provide detailed guidance on roundabouts, multimodal safety at alternative intersections, and intersection control evaluation (see Special Note A). Research is needed to develop a guide on several widely adopted intersection types, reflecting the growing knowledge and experience from successful implementations by many state departments of transportation (DOTs). The guide also will focus on expanding the toolbox of A.I.I. types and options to help DOTs enhance multimodal transportation safety and operational efficiency. OBJECTIVE: The objective of this research is to develop a guide to support state DOTs and other transportation agencies in considering A.I.I.s in their project planning and development process. The guide will consist of two parts: 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.

• Record URL:
  • http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=5679
• Supplemental Notes:
  • Contract to a Performing Organization has not yet been awarded.

Language

• English

Project

• Funding: $550,000
• Contract Numbers:

  Project 17-131

• Sponsor Organizations:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001
• Project Managers:

  Zhao, Yi

• Start Date: 20250113
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Bicycle safety; Highway design; Interchanges and intersections; Left turns; Pedestrian safety; Restricted crossing U turn intersections; Traffic conflicts; Traffic safety
• Subject Areas: Design; Highways; Pedestrians and Bicyclists; Safety and Human Factors;

Filing Info

• Accession Number: 01919348
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 17-131
• Files: TRB, RIP
• Created Date: May 22 2024 12:59PM