Development of guidelines for triple left and dual right-turn lanes : technical report.

Details

• Alternative Title:
  Project title: Development of guidelines for triple left and dual right-turn lanes
• Creators:
  Cooner, Scott A. ; Ranft, Stephen E. ; Rathod, Yatin K. ; Qi, Yi ; Yu, Lei ; Wang, Yubian ; Chen, Sammy
• Corporate Creators:
  Texas Transportation Institute
• Corporate Contributors:
  Texas. Dept. of Transportation. Research and Technology Implementation Office ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Turning lanes
  • Right turn lanes
  • Left turn lanes
  • Two way left turn lanes
  • Guidelines Turning lanes--Texas
• Publication/ Report Number:
  FHWA/TX-11/0-6112-1
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas
• Edition:
  Technical report; Sept. 2008-Aug. 2010.
• Corporate Publisher:
  Texas Transportation Institute
• Abstract:
  Left- or right-turn lanes at intersections improve safety and operations by separating turning and through vehicles. At intersections ; with heavy turning demand, it may be necessary to provide multiple turn lanes. Triple left-turn (TLT) and dual right-turn (DRT) ; lanes are still considered as relatively new designs that many agencies are reluctant to use, so they are somewhat limited in Texas. ; Guidelines for TLT or DRT lanes are almost nonexistent, leaving traffic engineers to rely on judgment for their designs. Therefore, ; this research was needed to develop consistent guidance. The 0-6112 project achieved two primary project goals: (1) development ; of geometric and signal design guidelines for TLT and DRT lanes; and (2) evaluation of the safety and operational performance of ; TLT and DRT sites in Texas. ; Researchers conducted field studies at 5 TLT and 20 DRT, primarily in the Dallas-Fort Worth and Houston urban areas, in order to ; evaluate lane utilization patterns, saturation flow rates, conflicts, and other operational factors. The research team also analyzed ; safety performance by investigating the crash history of the 25 sites using three techniques: collision diagrams, field conflict study, ; and comparison study. The results revealed that TLT lanes do not experience any major safety issues and also concluded that, in ; general, a well-designed DRT lane does not cause significantly higher crash frequency or severity compared to single right-turn ; lanes. ; Based on the results of this research and the geometric and signal design guidelines, TxDOT and other agencies should be ; confident that well-designed TLT and DRT lanes can be implemented to address heavy turning demand at key intersections. The ; evaluation of these multiple turn lane sites in Texas revealed that they perform well from both operational and safety standpoints. ; TLT and DRT lanes are not appropriate for all situations, and their use should be supported by an operational analysis. Other ; techniques (grade separation, signal timing, etc.) might be better solutions for a particular site, especially when considering the ; effects of adjacent intersections, pedestrian/bicycle movements, and other key factors. Researchers developed a product, Keys to ; Successful Public Outreach, which is useful for implementing multiple turn lane projects.
  More +
• Format:
  PDF
• Funding:
  Project 0-6112
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/23042/dot_23042_DS1.pdf
• File Type:
  [PDF - 5.17 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:cccb3dcfe3ad40bfd6c1b4c1532893c2259a25cc67bac1d88e72322e3843b53aefb5f17848a5e0d501fcdffa51e15b42dea7f8bd799e0ed3357ef31d8354909d