Design of Turn Lane Guidelines

The guidance in the Minnesota Department of Transportation's (MnDOT’s) Road Design Manual relative to the design of turn lanes is at least 35 years old and is reflective of a time when vehicle speed and volume were lower than they are today. In response to these current conditions, some designers have been providing longer turn lanes. However, this approach has resulted in inconsistent designs across MnDOT’s system. In response to concerns about the dated guidance in the Road Design Manual, the inconsistent treatment across the system and the lack of a documented design process, MnDOT developed and documented a new turn lane design process. The suggested design process is based on the notion that turn lanes should be designed to be long enough to accommodate deceleration from the prevailing highway speeds plus the storage needed for left or right turning vehicles. The new guidance provides a check list for designers that have links to look up tables for deceleration based on speed, storage based on volume of turning vehicles and type of intersection control and adjustments for grades and the fraction of heavy vehicles. These guidelines provide a resource for designers that will allow greater consistency between the length of turn lanes and traffic and roadway characteristics.

• Record URL:
  • https://hdl.handle.net/20.500.14153/mndot.2831
• 
• Summary URL:
  • http://www.lrrb.org/media/reports/201025TS.pdf
• Corporate Authors:

  CH2M HILL

  1295 Northland Drive, Suite 200
  Mendota Heights, MN  United States  55120

  Minnesota Department of Transportation

  Research Services Section, 395 John Ireland Boulevard, Mail Stop 330
  St Paul, MN  United States  55155
• Authors:
  • Preston, Howard
  • Farrington, Nicole
  • Elder, Michael
• Publication Date: 2010-70

Language

• English

Media Info

• Media Type: Web
• Edition: Final Report
• Features: Figures; Photos; Tables;
• Pagination: 60p

Subject/Index Terms

• TRT Terms: Geometric design; Guidelines; Turning lanes
• Geographic Terms: Minnesota
• Subject Areas: Design; Highways; I20: Design and Planning of Transport Infrastructure;

Filing Info

• Accession Number: 01444926
• Record Type: Publication
• Report/Paper Numbers: MN/RC 2010-25, Project MPR-9(003)
• Files: TRIS, STATEDOT
• Created Date: Sep 4 2012 4:00PM