Evaluating Permitted/Protected Versus Protected Left Turn Signals in Louisiana

The primary objective of this project is to study the safety and operation of existing signalized intersections (protected only versus permitted/protected left turns versus permitted only but with left turn lanes) along with their geometric features, as described in the Department of Transportation and Development (DOTD) Traffic Signal Manual, with the view to develop guidance on when it is appropriate to install each signal type. The research will answer whether or not the signal type affects the intersection control delay as well as if the signal type affects crash type and frequency. It will also investigate which geometric features significantly impact on the choice of signal type and if flow characteristics (traffic volumes) influence crash characteristics, and ultimately the choice of signal type. Finally, the research will explore when it is most appropriate to install a specific signal type considering operation and safety concerns.

Language

• English

Project

• Status: Active
• Funding: $197212
• Contract Numbers:

  21-3SS; 1000378

• Sponsor Organizations:

  Federal Highway Administration

  5304 Flanders Drive, Suite A
  Baton Rouge, LA  United States  70808
• Managing Organizations:

  Louisiana Transportation Research Center

  4101 Gourrier Avenue
  Baton Rouge, LA  United States  70808

  Louisiana Department of Transportation and Development

  Baton Rouge, LA  United States 
• Project Managers:

  Rupnow, Tyson

• Performing Organizations:

  Louisiana Transportation Research Center

  4101 Gourrier Avenue
  Baton Rouge, LA  United States  70808
• Principal Investigators:

  Codjoe, Julius

• Start Date: 20200801
• Expected Completion Date: 20220731
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Crash rates; Crash types; Exclusive permissive phasing; Exclusive phasing; Left turn lanes; Traffic signals; Traffic volume
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01754715
• Record Type: Research project
• Source Agency: Louisiana Transportation Research Center
• Contract Numbers: 21-3SS; 1000378
• Files: RIP, STATEDOT
• Created Date: Oct 15 2020 4:16PM