Automated highway systems (AHS) are not designated as stand-alone transportation facilities. Drivers will, by necessity, drive from their origins to the AHS entrance, and from the AHS exit to their final destinations. Therefore, the AHS will affect other transportation facilities, and should be integrated with all other facilities in the transportation system. Interfaces create much of the congestion for today's transportation systems and AHS interfaces may cause similar problems. If these problems exist, either the AHS or the conventional road network cannot function properly. The system as a whole may break down and the AHS could potentially become a detriment to the overall transportation system. Not enough is known about the automated merging process to determine what conditions would lead to congestion at interface points. Current macroscopic analysis techniques assume parameters that are not applicable to an AHS, and no detailed AHS merging models have been developed and validated. This paper addresses the interface problem between an AHS and a conventional roadway. It presents a microscopic simulation model for one scenario of the automated merging maneuver. Results of the model show that for low flows and conventional highway speeds, a 1-lane AHS merging section with a dedicated automated entrance ramp has similar characteristics to a 2-lane conventional freeway with or without fixed-time ramp metering. However, when the conventional freeway starts to break down near its capacity, the AHS continues to perform with little delay. The model also validates that the minimum ramp length requirements are a function of the merging vehicle's speed, the mainline vehicles' speed, and the acceleration and deceleration rates of the merging vehicle.

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    The Boulevard, Langford Lane
    Kidlington, Oxford  United Kingdom  OX5 1GB
  • Authors:
    • Ran, Bin
    • Leight, S
    • Chang, B
  • Publication Date: 1999-12


  • English

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  • Accession Number: 00791337
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Apr 4 2000 12:00AM