Double Crossover Diamond Interchange

Today's transportation professionals, with limited resources available to them, are challenged to meet the mobility needs of an increasing population. At many highway junctions, congestion continues to worsen, and drivers, pedestrians, and bicyclists experience increasing delays and heightened exposure to risk. Today's traffic volumes and travel demands often lead to safety problems that are too complex for conventional interchange designs to properly handle. Consequently, more engineers are considering various innovative treatments as they seek solutions to these complex problems. The corresponding technical report, Alternative Intersections/Interchanges: Informational Report (AIIR) (FHWA-HRT-09-060), covers four intersection designs and two interchange designs that offer substantial advantages over conventional at-grade intersections and grade-separated diamond interchanges. The AIIR provides information on each alternative treatment covering salient geometric design features, operational and safety issues, access management, costs, construction sequencing, environmental benefits, and applicability. This TechBrief summarizes information on one alternative interchange design—the double crossover diamond (DCD) interchange. The DCD interchange, also known as a diverging diamond interchange (DDI), is a new interchange design that has much in common with the design of a conventional diamond interchange. The main difference between a DCD interchange and a conventional diamond interchange is in the way left and through movements navigate between the cross street intersections with ramps. The DCD design accommodates left-turning movements onto arterials and limited-access highways while eliminating the need for a left-turn signal phase at signalized ramp terminal intersections. On the cross street, the traffic moves to the left side of the roadway between the signalized ramp intersections. This allows drivers of vehicles on the cross street who want to turn left onto the ramps the chance to continue to the ramps without conflicting with opposing through traffic and without stopping.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures;
  • Pagination: 4p
  • Serial:
    • TechBrief
    • Publisher: Federal Highway Administration
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 01149564
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-HRT-09-054
  • Files: NTL, TRIS, USDOT
  • Created Date: Jan 13 2010 12:46PM