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Abstract for presentation (Poster or Podium)

Street & Highway Operations

Operational Advantages of the One-Sided Displaced Partial Cloverleaf A4 Interchange Design

Sunday, June 16, 2024
1:15 PM - 2:30 PM ET
Room: Galleria

    Primary Author(s)

  • Peter Yu, n/a

    Undergraduate Research Assistant
    University of Washington
    Camas, Washington, United States

    • Presenter(s)

  • Peter Yu, n/a

    Undergraduate Research Assistant
    University of Washington
    Camas, Washington, United States

    • Co-Author(s)

  • Yinhai Wang

    Ph.D., P.E.
    Univ. of Washington
    Seattle, WA, United States

    • Submitter(s)

  • Peter Yu, n/a

    Undergraduate Research Assistant
    University of Washington
    Camas, Washington, United States

Abstract: The partial cloverleaf (parclo) A4 interchange provides numerous essential freeway-to-arterial connections. However, it tends to become congested with high arterial or off-ramp traffic demands. This congestion results in wasted time and fuel and may increase crash rates. Moreover, few studies in the literature have focused on improving safety and mobility at parclo A4 interchanges. To address these problems and narrow this research gap, this study proposes an alternative interchange design named the “one-sided displaced parclo A4 interchange” (OSDPAI). VISSIM analyzed and compared the OSDPAI to the traditional parclo A4 interchange and parclo progressA interchange—another alternative design—under multiple traffic demand scenarios. The simulation results indicate the OSDPAI substantially outperforms the parclo A4 interchange in travel time and throughput in all tested scenarios. The OSDPAI outperforms the parclo progressA interchange with dominant arterial through traffic. The OSDPAI and parclo progressA interchange perform similarly with moderate and high levels of left-turning traffic. The OSDPAI is a viable alternative for parclo A4 interchanges with high arterial through demands and/or high off-ramp demands.

Learning Objectives:

Attendees can expect to learn the following from this session:
  • Describe the key geometric design features of the one-sided displaced partial cloverleaf A4 interchange (OSDPAI)
  • Identify three site or traffic conditions in which the OSDPAI would be operationally advantageous
  • Identify two site or traffic conditions in which the OSDPAI would be economically advantageous