Investigation of Rural J-Turn Design Factors Using the ZouSim Driving Simulator (aka Driving Simulator Study of J-Turn Acceleration/Deceleration Lane and U-Turn Spacing Configurations)

The J-turn, also known as restricted crossing U-turn (RCUT) or superstreet, is an innovative geometric design that can improve intersection safety. Even though this design has been in use in several states for many years, there is very little research-based guidance for several design parameters. A driving simulator study was conducted to analyze the parameters of lane configuration, U-turn spacing, and signage. Two lane configurations were examined: 1) acceleration/deceleration configuration where acceleration and deceleration lanes are provided and 2) deceleration only configuration where only deceleration lanes are provided. Lane configuration was found to be the most important parameter affecting J-turn safety based on speed differentials. The only significant interaction effect among parameters was between lane configuration and U-turn spacing. The acceleration/deceleration configuration performed better than the deceleration only configuration with 66.3 percent fewer safety critical events. Vehicle trajectories and average lane-change locations showed that U-turn spacing impacted significantly the acceleration/deceleration configuration (i.e., average merge locations changed by 96 to 101 percent), but not the deceleration only configuration. No strong preference was demonstrated by the study subjects for either the directional or the diagrammatic signage style. This project represents the first human factors study of the J-turn focused on developing design guidance. This human factors approach complements other traditional approaches such as crash analysis and micro-simulation.

• Record URL:
  http://www.intrans.iastate.edu/mtc/index.cfm/research/project/project/514709633
• Record URL:
  http://www.intrans.iastate.edu/research/documents/research-reports/J-turn_ZouSim_w_cvr.pdf
• Record URL:
  http://www.intrans.iastate.edu/publications/_documents/t2summaries/J-turn_ZouSim_t2.pdf
• 

Language

• English

Project

• Status: Completed
• Funding: $268444
• Contract Numbers:

  DTRT13-G-UTC37

• Sponsor Organizations:

  Midwest Transportation Center

  Iowa State University
  2711 S Loop Drive, Suite 4700
  Ames, IA  United States  50010-8664

  Missouri Department of Transportation

  1617 Missouri Boulevard
  P.O. Box 270
  Jefferson City, MO  United States  65102

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590

  University of Missouri, Columbia

  Department of Civil Engineering
  Columbia, MO  United States  65211
• Managing Organizations:

  Midwest Transportation Center

  Iowa State University
  2711 S Loop Drive, Suite 4700
  Ames, IA  United States  50010-8664
• Performing Organizations:

  University of Missouri, Columbia

  Department of Civil Engineering
  Columbia, MO  United States  65211
• Principal Investigators:

  Sun, Carlos

  Edara, Praveen

  Nemmers, Charles

• Start Date: 20140901
• Expected Completion Date: 20161231
• Actual Completion Date: 20161231

Subject/Index Terms

• TRT Terms: Driving simulators; Geometric design; Intersections; Rural highways; Safety; Speed
• Identifier Terms: Driver Behavior Questionnaire
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 01622251
• Record Type: Research project
• Source Agency: Midwest Transportation Center
• Contract Numbers: DTRT13-G-UTC37
• Files: UTC, RIP
• Created Date: Jan 9 2017 12:07PM