A Guidance for Managed Lane Access Spacing Using the Gap Acceptance Theory-Based Capacity Estimation of Two-sided Type C Weaves

This paper investigates the impact of managed lane access spacing, the distance between the freeway on-ramp or off-ramp and managed lane slip ramp, on capacity and provides guidance for this spacing. Managed lanes are typically adjacent to the freeway median. On-ramp traffic that weaves across freeway mainlanes to a managed lane access point can be effectively modeled as a two-sided Type C weave. The HCM 2000 methodology can only provide the roughest of approximations when applied to a two-sided Type C weave. The high level of lane-changing activity present in weaving areas affects capacity significantly. One promising tool for the analysis of weaving area lane-changing activity is the gap acceptance theory. This paper estimates the capacity of two-sided Type C weaving areas based on the estimated degree of traffic turbulence using gap acceptance theory. The degree of traffic turbulence is a function of the probability that lane-changing vehicles can complete their maneuvers successfully without driving aggressively in a given distance. Once the capacity of two-sided Type C weaving areas is estimated, the minimum managed lane access spacing is determined where capacity with respect to the managed lane access spacing becomes stable.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Yang, Chulsu
  • Mattingly, Stephen P
• Conference:
  • Transportation Research Board 87th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2008-1-13 to 2008-1-17
• Date: 2008

Language

• English

Media Info

• Media Type: DVD
• Features: Figures; References; Tables;
• Pagination: 14p
• Monograph Title: TRB 87th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

• TRT Terms: Gap acceptance; Highway capacity; Highway facilities; Mainline metering; Managed lanes; Operations; Ramp metering; Traffic characteristics; Traffic congestion; Weaving traffic
• Subject Areas: Administration and Management; Highways; Operations and Traffic Management; Planning and Forecasting; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 01099174
• Record Type: Publication
• Report/Paper Numbers: 08-1793
• Files: TRIS, TRB
• Created Date: May 21 2008 7:05AM