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Mid-America Transportation Center

Investigating Operations at Geometrically Unconventional Intersections

Final Report
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Researchers

  • Principal Investigator: Anuj Sharma (asharma3@unl.edu 402-472-6391)
  • Project Status
    Complete
    Sponsors & Partners
  • Nebraska Department of Roads
  • Abstract
    This report documents the development of decision assistance curves (DAC) for unconventional intersections, particularly median U-turns (MUT), continuous flow intersections (CFI), and jughandles. The operational measure of effectiveness such as delay, fuel consumption, and emissions were computed. An economic analysis was performed to compute the net present value (NPV) of benefits of operation and benefit to cost ratio (B/C) by estimating user’s cost, non-user’s cost, construction cost, and operation and maintenance cost for the life cycle period. The DAC classified the region of optimal performance of rural unconventional intersections comprising of four-lane major streets and two-lane minor streets. DAC indicated that MUT is applicable for almost all levels of volume combinations of major and minor street approach volumes under the presence of low left turning traffic. For medium to high left turning traffic, jughandle and CFI performed optimally on high major street approach volumes. Furthermore, it was also observed that for a case with medium to high left turning volumes, the use of CFI would be optimal for high major street approach volumes and high minor street approach volumes at an unbalanced condition. The use of a jughandle would be optimal for high major street approach volumes and its performance got better with increasing minor street approach volume at a balanced condition. However, the jughandle performed better at high major street approach volume and low minor street approach volume at an unbalanced condition. The study developed a spreadsheet tool called SILCC to estimate the operational measure of effectiveness, as well as to perform a life cycle cost analysis. A sample case study performed on a 24-hour rural pattern volume indicated high NPV of operational benefits and high B/C related to MUT compared to all other intersections for new construction. Though the MUT-retrofit had the highest NPV, since the construction cost of MUT-retrofit is high, a jughandle-retrofit was found to have the highest B/C.
    Project Amount
    $ 89,622