Lane-Based Micro-Analytical Model of a Roundabout Corridor

There is a need for better modeling of network performance, especially the spread of queues in congested networks, so that system-wide effects are better identified. This is important in handling small network design cases such as freeway interchange roundabouts or roundabout corridors with greater confidence. This paper describes a lane-based micro-analytical network model and demonstrates it using a detailed example of staggered-T roundabouts. The model has been developed recently and implemented in the SIDRA INTERSECTION software. Two fundamental elements of the model are (i) determining the backward spread of congestion as queues on downstream lanes block upstream lanes, and (ii) applying capacity constraint to oversaturated upstream lanes for determining exit flow rates, thus limiting the flows entering downstream lanes. These two elements are highly interactive with opposing effects. Establishing the relationship between upstream and downstream lane flow rates and identifying lane change implications are also important aspects of the model. Estimation of lane capacities, lane flows and lane queues for downstream and upstream approaches is essential for reliable modeling of network performance since these parameters are highly interdependent. The new lane-based analytical network model differs from traditional network models which rely on modeling of "approaches" or "links" based on aggregation (and therefore losing details) of individual lane conditions, and are more concerned about forward movement of vehicle platoons. These models cannot identify backward spread of congestion reliably since saturation levels of individual lanes can differ significantly. Lane under-utilization due to various causes will also have substantial impacts on network performance. (A) For the covering abstract of this conference see ITRD record number 201309RT334E.

• Corporate Authors:

  INSTITUTE OF TRANSPORTATION ENGINEERS. DISTRICT 7 CANADA

  ,    
• Authors:
  • Akcelik, R
• Conference:
  • CALGARY 2013 - THE MANY FACES OF TRANSPORTATION
  • Location: Calgary Alberta, Canada
  • Date: 2013-4-7 to 2013-4-10
• Publication Date: 2013

Language

• English

Media Info

• Pagination: 11 p.
• Monograph Title: Calgary 2013 - The Many Faces of Transportation - Technical Compendium

Subject/Index Terms

• TRT Terms: Conferences; Highway capacity; Mathematical models; Queuing; Roundabouts; Simulation; Software; Traffic flow; Traffic lanes
• Geographic Terms: Canada
• ITRD Terms: 8018: Canada; 643: Capacity (road, footway); 645: Capacity (traffic network); 8525: Conference; 6473: Mathematical model; 6594: Queue; 438: Roundabout; 9103: Simulation; 8645: Software; 671: Traffic flow; 2827: Traffic lane
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; I71: Traffic Theory; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 01494265
• Record Type: Publication
• Source Agency: Transportation Association of Canada (TAC)
• Files: ITRD, TAC
• Created Date: Sep 24 2013 12:58PM