Evaluation of Alternative Geometric Designs on Highway Corridors - Case Study of J Turns

Alternative geometric designs such as J-turns, double crossover interchanges and continuous flow intersections have the potential to improve safety and traffic flow on freeways and arterials. The evaluation of such designs will provide information on their effectiveness and guidance for their proper deployment. J-turn intersection designs have been in operation in Maryland and North Carolina for years. They serve as an alternative to a two-way stop controlled intersection on high-speed roadways. By forcing the through and left turn movements from the minor street to turn right and make a U-turn at a downstream location, the J-turn design is safer due to fewer conflict points and less severe conflict types. Missouri Department of Transportation (DOT) has recently started using J-turn design as a corridor safety treatment on rural high-speed roads. As their first corridor deployment, MoDOT is constructing J-turns on an 8.5-mile stretch of U.S. 54 south of Jefferson City. This project will evaluate the safety and operational benefits of this J-turn deployment. The analysis will focus on several safety and operational performance measures, including conflicts, actual crash statistics, driver confusion measures, heavy vehicle maneuverability, gap acceptance, and travel time measures. The study findings assist Missouri and other Midwest states with new knowledge on the benefits of J-turn design and guidance on when to consider deploying J-turns as a corridor level safety treatment.

• Record URL:
  http://matc.unl.edu/research/research_projects.php?researchID=402

Language

• English

Project

• Status: Completed
• Funding: $24229.00
• Contract Numbers:

  DTRT12-G-UTC07

• Sponsor Organizations:

  Research and Innovative Technology Administration

  University Transportation Centers Program
  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Performing Organizations:

  University of Missouri, Columbia

  Columbia, MO  United States  65211
• Principal Investigators:

  Sun, Carlos

  Edara, Praveen

• Start Date: 20120601
• Expected Completion Date: 0
• Actual Completion Date: 20131231
• Source Data: RiP Project 33539

Subject/Index Terms

• TRT Terms: Geometric design; Highway design; Highway operations; Highway safety; Intersections; Traffic conflicts; Traffic flow
• Uncontrolled Terms: J turns
• Geographic Terms: Maryland; Missouri; North Carolina
• Subject Areas: Construction; Design; Geotechnology; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 01483124
• Record Type: Research project
• Source Agency: Mid-America Transportation Center
• Contract Numbers: DTRT12-G-UTC07
• Files: UTC, RIP
• Created Date: Jun 5 2013 1:01AM