01099174

Component

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.

01084478

08-1793

English

14p

2008

Transportation Research Board 87th Annual Meeting

DVD

Figures (8) ; References (12) ; Tables (5)

Gap acceptance; Highway capacity; Highway facilities; Mainline metering; Managed lanes; Operations; Ramp metering; Traffic characteristics; Traffic congestion; Weaving traffic

Administration and Management; Highways; Operations and Traffic Management; Planning and Forecasting; I72: Traffic and Transport Planning

Transportation Research Board Annual Meeting 2008 Paper #08-1793

TRIS, TRB

Jan 29 2008 4:09PM