As urban and suburban intersections become more congested, a possible remedy to the recurring traffic jam is to separate the grades of the intersecting roads in the form of diamond interchanges. A more economical intersection treatment is the split intersection. This treatment requires that the major road be separated into two one-way roads comparable to an at-grade diamond junction. The split intersection facilitates smoother traffic flows with less delay, and safety should be improved by reducing congestion and separating the opposing directions of traffic. The three major disadvantages of a split intersection are the high initial cost of construction and of right-of-way purchases, the likelihood of stopping at two intersections instead of one when the two signals are not well-coordinated, and the possible wrongway movements by unfamiliar drivers. Documented advantages of split intersections show an increase in capacity and a reduction in delay. The authors of this article conducted a delay comparison between single and split intersections using a traffic microsimulation model--CORSIM (CORridor SIMulation)--to provide insight into the benefits of conversion. The analyses showed that the split intersection accommodates higher volumes of traffic with less delay per vehicle than the single intersection. The delay differential between the two types of intersections increased as entering and left-turning volumes rose. A case study is presented as an economic analysis procedure for planning purposes.


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  • Accession Number: 00795601
  • Record Type: Publication
  • Files: TRIS, ATRI, USDOT
  • Created Date: Jul 9 2000 12:00AM