Design and Scope of Impact of Auxiliary Lanes

For decades, Texas Department of Transportation districts have constructed auxiliary lanes to support interchange ramp operations and to resolve congestion proximate to freeway entrance and exit ramps. While auxiliary lanes are built throughout Texas, the existing roadway design manuals/guidelines do not present all of the necessary design tools and details for design engineers. The objective of this research project was to develop implementation-oriented guidelines on the use of auxiliary lanes. To fulfill this goal, the researchers (1) reviewed and synthesized national and peer states’ practices, (2) conducted a survey of traffic engineers, (3) analyzed operational benefits from adding auxiliary lanes at the segment level, (4) used micro-simulation to identify scope of impacts of auxiliary lanes at the corridor level, (5) analyzed safety impacts of adding auxiliary lanes, and (6) developed guidelines and recommended best practices. The outcomes of this study provide important recommendations and numerical tools (e.g., the look-up tables) in implementing and designing freeway auxiliary lanes for new construction or rehabilitation projects. The developed methodologies and outcomes will complement the provisions in current state roadway design manuals/guidelines.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Technical Report
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 212p

Subject/Index Terms

Filing Info

  • Accession Number: 01529439
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-14/0-6706-1, 0-6706-1
  • Contract Numbers: 0-6706
  • Created Date: Jun 12 2014 11:23AM