Abstract: As one of the most popular unconventional interchange designs, diverging diamond intersection (DDI) has received increased
attention over the past decade. Through a reverse operation of traffic movements between its two crossover intersections, DDI can accommodate
more traffic movements within each phase. To design an effective signal plan for DDIs, one needs to address the following two critical
issues: (1) how to select the common cycle length and green splits at each crossover intersection under different geometric conditions, and
(2) how to coordinate a DDI’s two crossover intersections with its adjacent conventional intersections. To contend with these issues, this paper
presents an optimization model with the objective of maximizing intersection capacity to yield the optimal green splits and cycle length.
Also, in view of the potentially large left-turn traffic volumes from the freeway off-ramps, this study has further modified a model to provide
progressions to both left-turn and through traffic paths. Using simulation software as an unbiased tool, this study has conducted extensive
simulation comparisons between the optimized signal plans and the results from signal optimization software under various traffic scenarios.
The experimental results confirm the promising properties of the proposed signal models for DDI, especially if the traffic progression
between two crossover intersections is the major concern. DOI: 10.1061/(ASCE)TE.1943-5436.0000657. © 2014 American Society of
Civil Engineers.
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